Term Index (C)

• C:
  • Caldwell Catalog: small catalog for amateur astronomers as an adjunct to the Messier Catalog
  • Cambridge Catalog of Radio Sources (C): series of catalogs of northern hemisphere sources
  • carbon (C): element, C, atomic number 6
  • carbon star (C): star with more carbon than oxygen in its atmosphere
  • relativity: physics models accommodating the constancy of the speed of light
  • speed of light (c): fundamental constant measured as the speed at which light travels
• C band:
  • C-BASS: 6 cm survey of the entire sky
• C chondrite:
  • carbonaceous chondrite (C chondrite): stony meteorites with carbon compounds showing no melting
• C class:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• C*:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• C-band All Sky Survey:
  • C-BASS: 6 cm survey of the entire sky
  • Owens Valley Radio Observatory (OVRO): group of radio telescopes in California near the VLBA
• C-BASS: 6 cm survey of the entire sky
• C-BASS Telescope:
  • Owens Valley Radio Observatory (OVRO): group of radio telescopes in California near the VLBA
• C-COSMOS:
  • Cosmic Evolution Survey (COSMOS): investigation of dark matter and the universe's large scale structure
• C-H:
  • methylidyne (CH): compound of one carbon and one hydrogen atom
• C-type shock:
  • shock wave: abrupt propagating disturbance in a fluid
• C-type star:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• C. Donald Shane Telescope:
  • Shane Telescope: 3.05 m reflector telescope at Lick Observatory
• C/P:
  • Solar Maximum Mission (SMM): 1980s satellite to study the Sun during solar maximum
• C₂₀:
  • gravitational potential model: mathematical model of an astronomical body's gravitational field
• C₂₂:
  • gravitational potential model: mathematical model of an astronomical body's gravitational field
• C₂H₂:
  • acetylene (C₂H₂): compound of two carbon and two hydrogen atoms
• C₂H₄:
  • ethylene (C₂H₄): compound of two carbon and four hydrogen atoms
• C₃H₄:
  • tracer: chemical whose presence indicates the presence of another chemical
• C₆₀:
  • diffuse interstellar bands (DIBs): type of absorption bands seen in astronomical objects
  • polycyclic aromatic hydrocarbon (PAH): hydrocarbons consisting of meshes of benzene rings
• C_P:
  • specific heat: ratio of added temperature to added heat for a material
• C_V:
  • specific heat: ratio of added temperature to added heat for a material
• C⁺: ionized carbon missing one electron
  • carbon (C): element, C, atomic number 6
• Ca:
  • calcium (Ca): element, Ca, atomic number 20
• Ca I:
  • calcium (Ca): element, Ca, atomic number 20
• Ca II:
  • calcium (Ca): element, Ca, atomic number 20
• Ca II K line:
  • Wilson-Bappu effect: a relation between a star's spectral line and luminosity
• cadence: period between observations
• CAESAR: planned space mission to return a sample of a comet
• CAI: calcium/aluminum specs in chondrites
• Calán/Tololo Supernova Search:
  • Calán/Tololo Survey: late 1980s to early 1990s search to redshift 0.1
• Calán/Tololo Survey: late 1980s to early 1990s search to redshift 0.1
• Calar Alto 2.2 meter telescope:
  • Munich Near-Infrared Cluster Survey (MUNICS): 1990s-2000s galaxy cluster survey
• Calar Alto 3.5 meter telescope:
  • CALIFA: spectroscopic map of 600 galaxies
  • Munich Near-Infrared Cluster Survey (MUNICS): 1990s-2000s galaxy cluster survey
• Calar Alto Legacy Integral Field Area Survey:
  • CALIFA: spectroscopic map of 600 galaxies
• Calar Alto Observatory:
  • CALIFA: spectroscopic map of 600 galaxies
  • Munich Near-Infrared Cluster Survey (MUNICS): 1990s-2000s galaxy cluster survey
• calcium (Ca): element, Ca, atomic number 20
  • Am star: A-type star with metallic lines
• calcium carbonate:
  • carbonate-silicate cycle: long-term cycle that sequesters Earth carbon
  • silicate weathering feedback: feedback mechanism stabilizing carbon in Earth atmosphere
• calcium silicate:
  • carbonate-silicate cycle: long-term cycle that sequesters Earth carbon
  • silicate weathering feedback: feedback mechanism stabilizing carbon in Earth atmosphere
• calcium-aluminum-rich inclusion:
  • CAI: calcium/aluminum specs in chondrites
• calcium-rich gap transient: type of explosive event larger than a nova and smaller than a supernova
• calcium-rich supernova:
  • calcium-rich gap transient: type of explosive event larger than a nova and smaller than a supernova
• Caldwell:
  • Caldwell Catalog: small catalog for amateur astronomers as an adjunct to the Messier Catalog
• Caldwell 12:
  • NGC 6946: face-on spiral galaxy
• Caldwell 5:
  • IC 342: spiral galaxy in the Council of Giants
• Caldwell 79:
  • NGC 3201: globular cluster in which a black hole has been identified
• Caldwell Catalog: small catalog for amateur astronomers as an adjunct to the Messier Catalog
• CALIFA: spectroscopic map of 600 galaxies
• California:
  • Allen Telescope Array (ATA): array of radio telescopes in northern California for SETI
  • Automated Planet Finder (APF): robotic telescope to find exoplanets using RV method
  • BIMA telescope: millimeter interferometer in operation 1985 to 2005
  • CHARA: optical interferometer
  • COMAP: high frequency radio telescope to map CO
  • Combined Array for Research in Millimeter-wave Astronomy (CARMA): array of radio telescopes in eastern California
  • Hale Telescope: 5.1 m reflector telescope in California
  • Lick Observatory: California observatory of long standing
  • Lick Observatory Supernova Search (LOSS): search for supernovae for cosmological study
  • Livermore Optical Transient Imaging System (LOTIS): automated telescope aiming to catch GRB optical counterparts
  • Owens Valley Radio Observatory (OVRO): group of radio telescopes in California near the VLBA
  • Palomar 48 Inch Telescope (P48): 48 inch Schmidt telescope at Palomar Observatory
  • Palomar 60-inch Telescope (P60): 60 inch telescope at Palomar Observatory
  • Palomar Observatory: California observatory with Hale telescope
  • Palomar Testbed Interferometer (PTI): near-infrared interferometer experiment
  • Shane Telescope: 3.05 m reflector telescope at Lick Observatory
  • Sunyaev-Zel'dovich Array (SZA): array of eight 3.5 meter microwave telescopes
• California Extremely Large Telescope (CELT): concept for an extremely large telescope
• California-Kepler Survey (CKS): followup to Kepler to determine stellar radii
• Callisto: well-known Jupiter moon
• Caltech:
  • IPAC: Caltech group to collect and analyze infrared observations
  • Owens Valley Radio Observatory (OVRO): group of radio telescopes in California near the VLBA
  • Palomar Observatory: California observatory with Hale telescope
  • Two Micron Sky Survey (IRC,TMSS): 1969 infrared catalog produced by Caltech
• Caltech Infrared Catalog:
  • Two Micron Sky Survey (IRC,TMSS): 1969 infrared catalog produced by Caltech
• Caltech Submillimeter Observatory (CSO): 10.4 meter submillimeter telescope in Hawaii
• Camargo:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CAMB:
  • CMBFAST: software to calculate CMB anisotropies
• Cambridge Automated Plate Measuring Machine:
  • plate measuring machine (APM): machine to measure position of images on photographic plates
• Cambridge Automatic Plate Measuring Machine:
  • APM Galaxy Survey (APMUKS): 1990s survey of galaxies in southern sky
• Cambridge Catalog of Radio Sources (C): series of catalogs of northern hemisphere sources
• Cambridge Interferometer:
  • Third Cambridge Catalogue of Radio Sources (3C): 1959 catalog of northern hemisphere 159MHz sources
• Cambridge OH Suppression Instrument:
  • United Kingdom Infrared Telescope (UKIRT): Mauna Kea 3.8 meter infrared telescope
• Cambridge Optical Aperture Synthesis Telescope:
  • COAST: optical interferometer in England
• Camelopardalis:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• camera:
  • GISMO: 2 mm bolometer camera on IRAM 30 m telescope
  • MUSTANG: bolometer array on the Green Bank Telescope
  • QUEST: sixteen square-degree survey camera
  • SCUBA: submillimeter instrument on James Clark Maxwell Telescope
  • TolTEC: sensitive infrared camera under construction for the LMT
• cameras:
  • image stabilization: camera mechanism to compensate for movement
• CAMISTIC:
  • Infrared Telescope Maffei (ITM,IRAIT): 80 cm infrared telescope in Antarctica
• Campo Imperatore:
  • Campo Imperatore Near-Earth Object Survey (CINEOS): survey of near-Earth objects
• Campo Imperatore Near-Earth Object Survey (CINEOS): survey of near-Earth objects
• CAMS:
  • ASTRO-H: Japanese space X-ray telescope
• Canada:
  • Canadian Hydrogen Intensity Mapping Experiment (CHIME,CH): radio telescope mapping distant neutral hydrogen
  • Canadian Institute for Theoretical Astrophysics (CITA,ICAT): national research organization at University of Toronto
  • CSA: includes astronomical research
  • Dominion Observatory 10.03 MHz Source Catalog (DB): 1960s survey of northern-hemisphere radio sources
  • Dominion Observatory 1420 MHz Source Catalog (DA): 1960s survey of northern-hemisphere radio sources
  • Dominion Radio Astrophysical Observatory (DRAO): radio observatory in British Columbia, Canada
  • Large Zenith Telescope (LZT): 6 meter liquid mirror telescope in British Columbia
  • Queen's University Radio Observatory (QRO): early radio astronomy facility near Kingston, Ontario
  • Saskatoon: 1990s survey to measure CMB anisotropy
• Canada-France Brown Dwarfs Survey:
  • CFBDS: survey in search of brown dwarfs
• Canada-France High-z Quasar Survey (CFHQS): 2000s distant quasar survey
• Canada-France Redshift Survey (CFRS): 1990s survey of galaxies to z = 1 to find associations of redshift to characteristics
• Canada-France-Hawaii Telescope (CFHT): 3.6 meter optical/infrared telescope in Hawaii
  • Canada-France High-z Quasar Survey (CFHQS): 2000s distant quasar survey
  • Canada-France Redshift Survey (CFRS): 1990s survey of galaxies to z = 1 to find associations of redshift to characteristics
  • Canadian Cluster Comparison Project (CCCP): multi-wavelength survey of fifty X-ray-selected galaxy clusters
  • CFHTLS: surveys of transients and stars
  • Outer Solar System Origins Survey (OSSOS): survey searching for trans-Neptune objects
  • SPIRou: CFHT spectropolarimeter for exoplanet research
• Canada-France-Hawaii Telescope Legacy Survey:
  • CFHTLS: surveys of transients and stars
• Canadian Cluster Comparison Project (CCCP): multi-wavelength survey of fifty X-ray-selected galaxy clusters
• Canadian Hydrogen Intensity Mapping Experiment (CHIME,CH): radio telescope mapping distant neutral hydrogen
• Canadian Hydrogen Observatory and Radio-transient Detector:
  • Canadian Hydrogen Intensity Mapping Experiment (CHIME,CH): radio telescope mapping distant neutral hydrogen
• Canadian Institute for Theoretical Astrophysics (CITA,ICAT): national research organization at University of Toronto
• Canadian Space Agency:
  • CSA: includes astronomical research
• CanariCam:
  • Gran Telescopio Canarias (GTC): 10.4 meter telescope in the Canary Islands
• Canary Islands:
  • Cherenkov Telescope Array (CTA): ground gamma-ray telescope array in development
  • COSMOSOMAS: microwave survey
  • Gran Telescopio Canarias (GTC): 10.4 meter telescope in the Canary Islands
  • HARPS-N: high-precision spectrograph for exoplanet searches in Canary Islands
  • Isaac Newton Group of Telescopes (ING): three telescopes in Canary Islands
  • Isaac Newton Telescope (INT): 2.5 m telescope in Canary Islands
  • LSPE-STRIP: CMB survey telescope in Canary Islands
  • Mercator Telescope: 1.2 m telescope in the Canary Islands
  • Overwhelmingly Large Telescope (OWL): 100 m telescope plan
  • QUIJOTE: survey to measure the polarization of the CMB
  • Roque de los Muchachos Observatory (ORM,LPO,NHO): observatory at La Palma in the Canary Islands
  • SuperWASP (SWASP): broad Earth-based search for transiting planets
  • Teide Observatory: observatory on Mount Teide in the Canary Islands
  • Telescopio Nazionale Galileo (TNG): 3.58 m telescope in Canary Islands
  • Tenerife Experiment: 1980s-1990s survey of CMB anisotropies
  • Thirty Meter Telescope (TMT): extremely large telescope planned for Hawaii
  • Very Small Array (VSA): radio interferometer in Canary Islands
  • William Herschel Telescope (WHT): 4.2 meter telescope in the Canary Islands
• Canberra Deep Space Communication Complex:
  • NASA Deep Space Network (NASA DSN,DSN): NASA's world-wide radio communication setup
• CANCAM:
  • CAESAR: planned space mission to return a sample of a comet
• CANDELS:
  • Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS): early universe survey by HST
• candidate companion (CC): possible object apparently orbiting a known object
• Canes Venatici Cloud:
  • galaxy cloud: substructure of a supercluster
• Canes Venatici I:
  • Milky Way subgroup: the Milky Way and its satellites
• Canes Venatici II:
  • Milky Way subgroup: the Milky Way and its satellites
• Canis Major:
  • Milky Way subgroup: the Milky Way and its satellites
• Canis Major Dwarf Galaxy: small irregular galaxy in the Local Group
• Canis Major Overdensity:
  • Canis Major Dwarf Galaxy: small irregular galaxy in the Local Group
• canonical pulsar:
  • millisecond pulsar (MSP): pulsar spinning with a period in the range of milliseconds
• Canopus: second brightest star in the sky
• capacitance:
  • dielectric: insulator that responds to an electric field
• capacitor:
  • dielectric: insulator that responds to an electric field
• Cape Photographic Durchmusterung:
  • Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
• CAPMAP: early 2000s array that surveyed CMB polarization
• CAPS:
  • Cassini: explorer spacecraft sent to Saturn
• capture theory:
  • nebular hypothesis: model positing solar system planets result from a solar disk
• captured rotation:
  • tidal locking: locked rotation of an orbiting body
• carbide planet:
  • carbon planet: theoretical planet type with more carbon than oxygen
• carbon (C): element, C, atomic number 6
  • acetylene (C₂H₂): compound of two carbon and two hydrogen atoms
  • alpha CO (α_CO): ratio of CO emissions to H₂
  • C⁺: ionized carbon missing one electron
  • carbon burning: fusion reaction starting with carbon
  • carbon dioxide (CO₂): compound of carbon atom and two oxygen atoms
  • carbon monoxide (CO): compound of carbon and oxygen, one atom each
  • carbon planet: theoretical planet type with more carbon than oxygen
  • carbon star (C): star with more carbon than oxygen in its atmosphere
  • carbonate-silicate cycle: long-term cycle that sequesters Earth carbon
  • ethylene (C₂H₄): compound of two carbon and four hydrogen atoms
  • hydrocarbon (HC): any compound of just carbon and hydrogen
  • ionized carbon fine structure line ([CII]): carbon line that traces distant star formation
  • methane (CH₄): compound of one carbon and 4 hydrogen atoms
  • methylidyne (CH): compound of one carbon and one hydrogen atom
  • neutrons from carbon-13: process by which neutrons are freed in the s process
  • polycyclic aromatic hydrocarbon (PAH): hydrocarbons consisting of meshes of benzene rings
  • silicate weathering feedback: feedback mechanism stabilizing carbon in Earth atmosphere
• carbon burning: fusion reaction starting with carbon
  • magnesium (Mg): element, Mg, atomic number 12
  • neon (Ne): element, Ne, atomic number 10
  • nucleosynthesis: creation of atomic nuclei
  • sodium (Na): metal, Na, atomic number 11
• Carbon CII Line in Post-Reionization and Reionization Epoch:
  • CONCERTO: spectrometer aimed at mapping the [CII] line
• carbon cycle:
  • carbon dioxide (CO₂): compound of carbon atom and two oxygen atoms
• carbon dating:
  • radioactive dating: determining the age of a substance that has a radioactive component
• carbon deflagration:
  • Type Ia supernova: type of supernova for which distance can be determined
• carbon detonation:
  • Type Ia supernova: type of supernova for which distance can be determined
• carbon dioxide (CO₂): compound of carbon atom and two oxygen atoms
  • acidity (pH): measure of the activity of hydrogen ions in a solution
  • carbonate system: system governing water and CO2 in the presence of each other
  • carbonate-silicate cycle: long-term cycle that sequesters Earth carbon
  • silicate weathering feedback: feedback mechanism stabilizing carbon in Earth atmosphere
• carbon fusion:
  • carbon burning: fusion reaction starting with carbon
• carbon monosulfide:
  • tracer: chemical whose presence indicates the presence of another chemical
• carbon monoxide (CO): compound of carbon and oxygen, one atom each
• Carbon Monoxide Mapping Array (COMA): planned experiment to observe epoch of reionization
• Carbon Monoxide Power Spectrum Survey:
  • COPSS: survey of CO from star forming epoch
• carbon planet: theoretical planet type with more carbon than oxygen
• carbon star (C): star with more carbon than oxygen in its atmosphere
• carbon to oxygen ratio:
  • carbon (C): element, C, atomic number 6
• carbon, nitrogen$#44; oxygen:
  • CNO cycle: fusion reaction chain turning hydrogen and nitrogen into helium and nitrogen
• carbon-14:
  • radioactive dating: determining the age of a substance that has a radioactive component
• carbon-burning shell:
  • carbon burning: fusion reaction starting with carbon
• carbon-enhanced metal.page-poor:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• carbon-oxygen white dwarf:
  • white dwarf (WD): stellar remnant of mostly electron degenerate matter
• carbon-rich Wolf-Rayet:
  • Wolf-Rayet star: type of star with broad emission bands
• carbonaceous chondrite (C chondrite): stony meteorites with carbon compounds showing no melting
• carbonate:
  • acidity (pH): measure of the activity of hydrogen ions in a solution
  • carbonate system: system governing water and CO2 in the presence of each other
• carbonate system: system governing water and CO2 in the presence of each other
• carbonate-silicate cycle: long-term cycle that sequesters Earth carbon
  • weathering: changes in surface due to contact with atmosphere
• carbonic acid:
  • acidity (pH): measure of the activity of hydrogen ions in a solution
  • carbonate system: system governing water and CO2 in the presence of each other
• carbyne:
  • methylidyne (CH): compound of one carbon and one hydrogen atom
• Carina:
  • Milky Way subgroup: the Milky Way and its satellites
  • rare designator prefixes: designator prefixes generally used for only a few objects
• Carina-Sagittarius Arm:
  • spiral arm: long, winding visible structure within a spiral galaxy
• Carl Sagan Institute (CSI): group researching finding life on other planets and moons
• Carl Sagan Memorial Station:
  • Mars Pathfinder (MPF): 1990s mission to Mars with rover
• Carlsberg Meridian Catalogue (CMC): series of astrometric catalogs from 19th century on
• Carlsberg Meridian Telescope:
  • Carlsberg Meridian Catalogue (CMC): series of astrometric catalogs from 19th century on
• CARMA:
  • Combined Array for Research in Millimeter-wave Astronomy (CARMA): array of radio telescopes in eastern California
  • Owens Valley Radio Observatory (OVRO): group of radio telescopes in California near the VLBA
• CARMA EDGE: CO survey of galaxies
• CARMA Extragalactic Database for Galaxy Evolution:
  • CARMA EDGE: CO survey of galaxies
• Carnegie Institute for Science:
  • Carnegie Supernova Project (CSP): survey of supernovae lightcurves
• Carnegie Supernova Project (CSP): survey of supernovae lightcurves
• Carrington event: solar storm September 1-3 1859
• Cart du Ciel:
  • Astrographic Catalog (AC): historical star catalog of the whole sky to magnitude 11
• Cas:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• Cas A:
  • Cassiopeia A: supernova remnant visible for 300 years
• CASA: software package for radio interferometry image generation
• Case-Hamburg Survey (LS): 1950s-1970s survey(s) of OB stars
• Cassegrain reflector: reflector telescope with convex secondary mirror
• Cassegrain telescope:
  • Cassegrain reflector: reflector telescope with convex secondary mirror
• Cassini: explorer spacecraft sent to Saturn
  • radio science: radar and other methods of using radio to probe planets and moons
• Cassini Equinox:
  • Cassini: explorer spacecraft sent to Saturn
• Cassini Solstice:
  • Cassini: explorer spacecraft sent to Saturn
• Cassini-Huygens:
  • Cassini: explorer spacecraft sent to Saturn
• Cassiopeia A: supernova remnant visible for 300 years
• CaSSIS:
  • Trace Gas Orbiter (TGO): ESA and Russian Mars orbiter-probe launched in 2016
• Castro: hydrodynamics simulation software
• casually connection regions:
  • inflation: theorized rapid expansion of the very early universe
• CAT:
  • Cosmic Anisotropy Telescope (CAT): 1990s interferometer to measure CMB variations
• cataclysmic variable:
  • cataclysmic variable star (CV): star whose magnitude is much brighter on occasion
• cataclysmic variable star (CV): star whose magnitude is much brighter on occasion
  • variable star: star that varies in magnitude
• Catalina Real-time Transient Survey:
  • Catalina Sky Survey (CSS): survey of near-Earth objects
• Catalina Sky Survey (CSS): survey of near-Earth objects
• catalog:
  • 87GB Catalog of Radio Sources (87GB): 1980s Green Bank radio survey
  • Abell Catalog: galaxy cluster catalog assembled over 1950s-1980s
  • Aitken Double Star Catalogue (ADS): 1932 catalog with both multiple-star systems and non-orbiting double stars
  • All-Sky Compiled Catalogue (ASCC,ASCC-2.5): 2001 catalog compiled from modern sources
  • Arakelian Catalog (Ark): 1970s list of small/bright galaxies
  • Arecibo General Catalog (AGC): catalog of galaxies to support ALFALFA surveys
  • Arecibo Occultation Survey (AO): 1960s radio survey using occultations by the Moon
  • Arp-Madore Catalog of Southern Peculiar Galaxies (AM): 1970s-1980s catalog from the UK Schmidt Survey
  • Asiago Supernova Catalog (B/SN): 1999 catalog of known supernovae and their galaxies
  • Astrographic Catalog (AC): historical star catalog of the whole sky to magnitude 11
  • astronomical catalog: lists of observed astronomical bodies and their characteristics
  • Astronomische Gesellschaft Katalog (AGK): 19th/20th century astrometric catalog
  • Atlas of Galactic Nebulae (GN): 1980s catalog of Milky-Way nebulae
  • Atlas of Peculiar Galaxies (APG): 1960s catalog-book with photos
  • ATNF Pulsar Catalogue: online catalog of pulsars
  • Barnard Catalog (Barnard,B): 1919 catalog of dark nebulae
  • Basel Open Cluster Catalogue (Basel): list of open clusters
  • Becker, White, and Edwards Catalog (BWE): 1990s radio catalog from a Green Bank 300ft Telescope survey
  • Berkeley Open Cluster Catalogue (Be): list of open clusters
  • Bibliographic Catalog of Variable Stars (BCVS): listing of references to variable stars
  • Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
  • Boss General Catalog (GC): 1937 catalog of 30,000 stars
  • Bright Star Catalog (HR,BS,YBS): early 20th century catalog of 9000 stars
  • Burnham Double Star Catalogue (BDS,BU): 1906 catalog with multiple star systems and non-orbiting double stars
  • Caldwell Catalog: small catalog for amateur astronomers as an adjunct to the Messier Catalog
  • Cambridge Catalog of Radio Sources (C): series of catalogs of northern hemisphere sources
  • Carlsberg Meridian Catalogue (CMC): series of astrometric catalogs from 19th century on
  • Catalog of Azzopardi & Vigneau (AzV): probable stars in the SMC
  • Catalog of Circumpolar Stars (Groombridge): list of over 4000 stars in northern part of the sky
  • Catalog of Components of Double and Multiple Stars (CCDM): 1994 catalog of 74000 such double-star components
  • Catalog of Galaxies and Clusters of Galaxies (CGCG): list of galaxies/clusters assembled in 1960s
  • Catalog of Infrared Observations (CIO): collection of infrared observation data from numerous sources
  • Catalog of Stellar Identifications (CSI): 1970s catalog cross referencing existing star catalogs
  • Catalogue of Cometary Orbits (CCO): comet catalog updated since 1970s
  • Catalogue of Galactic Planetary Nebulae (PK,PK67): 1967 catalog
  • Catalogue of Interacting Galaxies (VV): begun in the 1950s
  • Catalogue of Southern Double Stars: 1955 catalog with multiple star systems and non-orbiting double stars
  • Catalogues of Fundamental Stars: series of astrometric catalogs from 19th century on
  • Cederblad Catalog (Ced): list of bright nebulae
  • Collinder Catalog (Cr): 1930s catalog of 471 open clusters
  • Cosmic Lens All-sky Survey (CLASS): radio survey aimed at gravitational lenses
  • CRATES: catalog of 8.4 GHz data on radio sources
  • Czernik Catalog (Cz): list of open clusters
  • David Dunlap Observatory Catalog (DDO): catalog of dwarf galaxies
  • Dickel-Wendker-Bieritz Catalog (DWB): list of HII regions in the Cygnus X star forming region
  • Dolidze-Dzimselejsvili Catalogue (DoDz): list of 11 open clusters
  • Dunlop Double Star Catalogue (DUN): 1829 catalog of double stars viewed from Australia
  • Duus-Newell catalog (DN): list of southern galaxies/clusters assembled in 1970s
  • ESO/Uppsala Survey of the ESO (B) Atlas: 1970s southern all-sky survey
  • Fairall Galaxy List (Frl,Fairall): 1977 list of galaxies with bright nuclei
  • Fourth Cambridge Catalog of Radio Sources (4C): 1960s catalog of northern hemisphere 178 MHz sources
  • Frank Ross's Catalog (Ross): high-proper-motion and variable stars catalogued by Frank Ross
  • Galactic O Star Catalog (GOSC,GOS): 2000s catalog of O-type stars
  • General Catalog of Trigonometric Parallaxes (GCTP): 1950s star catalog with later updates
  • General Catalogue of Stellar Radial Velocities (GCRV): 1950s century catalog of 1500 stars with radial velocities
  • General Catalogue of Trigonometric Parallaxes (GCTP): 1950s catalog of stars with parallax measures
  • General Catalogue of Variable Stars (GCVS): 20th/21st century catalog of 58000 variable stars
  • Gliese Catalogue of Nearby Stars (Gl,Gliese): 1950s catalog of stars within 20 parsecs
  • Gliese-Jahreiss Catalog (GJ): 1991 catalog of stars within 25 parsecs
  • Green Bank 6-cm Radio Source Catalog (GB6): catalog of from 1980s northern-hemisphere radio survey
  • Guide Star Catalog (GSC,HSTGC): catalog of stars to help aim HST
  • Henry Draper Catalog (HD): early 20th century spectroscopic catalog of stars
  • Herschel Double Star Catalog (H): series of early double star catalogs
  • Herz catalog (Herz): list of 3000 stars in a strip of the southern sky
  • Index Catalog (IC): 1895 catalog of galaxies, star clusters, and other nebulae
  • ITEP-SAI Supernova Light Curve Catalogue: online catalog
  • King Catalog: list of 21 open clusters
  • Lépine Shara Proper Motion catalog (LSPM): 2000s catalog of stars with proper motion
  • Lacaille Star Catalog (Lac): 1700s catalog of about 10,000 southern hemisphere stars
  • Lowell Proper Motion Survey (G): 1950s-1970s catalogs of stars with proper motion
  • Luyten Double Star Survey (LDS): 1940s-1970s catalog of double stars
  • Luyten Half-second Catalog (LHS): 1979 catalog of 4000 stars with high proper motion
  • Luyten Palomar Survey (LP): 1960s catalog of stars with high proper motion
  • Luyten Two-Tenths Arcsecond Catalog (LTT): 1960 catalog of 9000+ stars with proper motion
  • Lynds Catalog of Dark Nebulae (LDN,L): 1950s/1960s list of dark nebulae found on Palomar plates
  • Lynds Catalogue of Bright Nebulae (LBN): 1950s/1960s list of bright nebulae found on Palomar plates
  • MASH Catalog of Planetary Nebulae: 995 possible planetary nebulae
  • Max Wolf's catalog of stars with proper motion: early 20th century catalog of 1500 stars
  • Melotte Catalog: 1915 catalog of open and globular clusters
  • Messier Catalog (M): catalog of astronomical objects to avoid when looking for comets
  • MIT X-ray Burst Source Catalog (MXB): 1970s catalog of X-ray bursters
  • Morphological Catalogue of Galaxies (MCG): 1960s catalog from Palomar plates
  • MSH Catalog (MSH): 1950s catalog of radio sources from a Mills Cross survey
  • N30 Catalog: 1950s catalog collecting proper motion data from older catalogs
  • New Catalogue of Suspected Variable Stars (NSV): catalog from latter half of 20th century catalog
  • New General Catalogue (NGC): 1888 catalog of galaxies, star clusters, and other nebulae
  • NOMAD: astrometric star catalog
  • Ohio Radio Survey (OSS): 1960s radio survey by Ohio State University
  • Open Exoplanet Catalogue (OEC): independently maintained list of known exoplanets
  • Palomar Globular Clusters (Pal): list of 15 globular clusters found in POSS plates
  • Palomar-Haro-Luyten Catalog (PHL): 1960s catalog of faint blue stars
  • Pantheon: catalog of well-checked Type Ia supernovae
  • Parkes Catalog (PKS): catalog of from 1960s-1990 of radio sources in southern hemisphere
  • Parsamian Nebula Catalog: 1965 list of nebulae
  • Polar-ring Catalog (PRC): 1990 catalog of polar-ring galaxies
  • PPM Star Catalogue: 1991 astrometric catalog with proper motions
  • Principal Galaxies Catalog (PGC): modern catalog of more than 70k galaxies
  • Radcliffe Observatory Magellanic Clouds Catalogue (RMC): catalog of stars in
  • RASS/Green Bank Catalog (RGB,RASSGB): combined list of radio galaxies from Rosat and Green Bank surveys
  • Reference Catalogue of Bright Galaxies (RC,RC1): series of catalogs of nearby galaxies
  • Roma-BZCAT: 2008 catalog of blazars
  • SAO Star Catalog: 1960s catalog
  • Shapley-Ames Catalog (SAC): 1932 catalog of contemporary data on 1249 galaxies
  • Sharpless Catalog (Sh2): catalog of HII regions found on Palomar plates
  • Spectroscopic Properties of Cool Stars (SPOCS): analysis of spectroscopic data of 7000+ M and L stars
  • Strasbourg-ESO Catalog of Galactic Planetary Nebulae (PNG): 1992 catalog of 1820 objects
  • Struve Catalogs: two catalogs of double stars
  • Texas Survey of Radio Sources at 365 MHz (TXS): 1970s/1970s radio survey made with the Texas Interferometer
  • Third Cambridge Catalogue of Radio Sources (3C): 1959 catalog of northern hemisphere 159MHz sources
  • Transient Name Server (TNS): online catalog of transients
  • Uppsala General Catalogue (UGC): 1973 catalog of galaxies visible from northern hemisphere
  • USNO CCD Astrograph Catalog (UCAC): USNO star catalog including proper motions
  • USS Sources: catalog of sources with steep spectral index
  • Van Den Bergh Reflection Nebula Catalog (vdB): catalog of reflection nebulae found in POSS plates
  • Villanova White Dwarf Catalog: ongoing catalog of white dwarfs
  • Virgo Cluster Catalog (VCC): 1980s catalog of 2000 galaxies
  • Washington Double Star Catalog (WDS): modern database of double stars
  • WISeREP: interactive catalog of supernovae
• Catalog of 5,268 Standard Stars, 1950.0 Based on the Normal System N30:
  • N30 Catalog: 1950s catalog collecting proper motion data from older catalogs
• Catalog of Azzopardi & Vigneau (AzV): probable stars in the SMC
• Catalog of Circumpolar Stars (Groombridge): list of over 4000 stars in northern part of the sky
• Catalog of Components of Double and Multiple Stars (CCDM): 1994 catalog of 74000 such double-star components
• Catalog of Dark Nebulae:
  • Lynds Catalog of Dark Nebulae (LDN,L): 1950s/1960s list of dark nebulae found on Palomar plates
• Catalog of Galaxies and Clusters of Galaxies (CGCG): list of galaxies/clusters assembled in 1960s
• Catalog of Infrared Observations (CIO): collection of infrared observation data from numerous sources
• Catalog of Nearby Stars:
  • Gliese Catalogue of Nearby Stars (Gl,Gliese): 1950s catalog of stars within 20 parsecs
• Catalog of Stellar Identifications (CSI): 1970s catalog cross referencing existing star catalogs
• catalog-based designator:
  • survey-based designator: astronomical object designators based on name of survey
• catalogs:
  • Astrocats: software to create and manage an astronomy catalog
  • astronomical catalog: lists of observed astronomical bodies and their characteristics
• catalogue:
  • astronomical catalog: lists of observed astronomical bodies and their characteristics
• Catalogue des Nebuleuses et des Amas d'Etoiles:
  • Messier Catalog (M): catalog of astronomical objects to avoid when looking for comets
• Catalogue of Bright Nebulae:
  • Lynds Catalogue of Bright Nebulae (LBN): 1950s/1960s list of bright nebulae found on Palomar plates
• Catalogue of Cometary Nebulae Discovered on Palomar Maps:
  • Parsamian Nebula Catalog: 1965 list of nebulae
• Catalogue of Cometary Orbits (CCO): comet catalog updated since 1970s
• Catalogue of Galactic Planetary Nebulae (PK,PK67): 1967 catalog
• Catalogue of Interacting Galaxies (VV): begun in the 1950s
• Catalogue of Nearby Stars:
  • Gliese-Jahreiss Catalog (GJ): 1991 catalog of stars within 25 parsecs
• Catalogue of Nebulae and Clusters of Stars:
  • New General Catalogue (NGC): 1888 catalog of galaxies, star clusters, and other nebulae
• Catalogue of Nebulae and Star Clusters:
  • Messier Catalog (M): catalog of astronomical objects to avoid when looking for comets
  • nebula: cloud of dust and gas
• Catalogue of Rich Clusters of Galaxies:
  • Abell Catalog: galaxy cluster catalog assembled over 1950s-1980s
• Catalogue of Southern Double Stars: 1955 catalog with multiple star systems and non-orbiting double stars
• Catalogues of Fundamental Stars: series of astrometric catalogs from 19th century on
• Catalogus Britannicus:
  • Flamsteed designation: star designation system dating from 1700s
• cation:
  • ion: non-neutral atom or molecule, with missing or extra electrons
• CATS345:
  • Atacama Submillimeter Telescope Experiment (ASTE): ten meter submillimeter telescope in Chile
• Cauchy distribution:
  • Lorentzian distribution: probability distribution applicable to some physics phenomena
• caustic structure:
  • core-cusp problem: theories and observation show different dwarf galaxy rotation curves
• cavity-enhanced absorption spectroscopy (CEAS): passing a beam through a gas multiple times to amplify absorption lines
• CB:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CBB:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CBI:
  • Cosmic Background Imager (CBI): radio telescope in Chile observing the CMB
  • Llano de Chajnantor Observatory: group of observatories on a high plateau of the Atacama Desert
• CBR:
  • cosmic background radiation (CBR): electromagnetic radiation coming from every direction
  • cosmic gamma ray background (CGB): gamma-ray radiation seen everywhere
  • cosmic infrared background (CIB,CIBR): widespread infrared radiation not associated with known sources
  • cosmic microwave background (CMB,CMBR,CBR,MBR): microwave radiation coming from every direction
  • cosmic optical background (COB): widespread optical radiation not associated with known sources
  • cosmic X-ray background (CXB,CXRB,CXBR): X-ray radiation coming from outside the Milky Way
  • diffuse emission: electromagnetic radiation not confined to a point source
  • extragalactic background light (EBL): electromagnetic radiation from star formation and AGNs
• CC:
  • candidate companion (CC): possible object apparently orbiting a known object
• CCAT: 25-meter submillimeter telescope plan for Chile
  • Atacama Desert: high altitude, dry plateau in Chile, the site of observatories
  • Llano de Chajnantor Observatory: group of observatories on a high plateau of the Atacama Desert
• CCAT-p:
  • Atacama Desert: high altitude, dry plateau in Chile, the site of observatories
  • Fred Young Submillimeter Telescope (FYST,CCAT-p): planned 6-meter submillimeter telescope in Chile
• CCAT-prime:
  • Fred Young Submillimeter Telescope (FYST,CCAT-p): planned 6-meter submillimeter telescope in Chile
• CCCP:
  • Canadian Cluster Comparison Project (CCCP): multi-wavelength survey of fifty X-ray-selected galaxy clusters
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CCCS:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CCD: electronic device to detect light
  • ACIS: imaging spectrometer on Chandra X-ray telescope
  • color-color diagram (CCD): means of comparing characteristics of stars
  • parts per million (PPM): method of expressing a small ratio
  • photometry: studying starlight through bandpass filters
  • quantum efficiency (QE): measure of instrument's ability to sense EMR
• CCD photometry:
  • photometry: studying starlight through bandpass filters
• CCDM:
  • Catalog of Components of Double and Multiple Stars (CCDM): 1994 catalog of 74000 such double-star components
• CCDs:
  • integration time: time required to acquire signal
• CCO:
  • Catalogue of Cometary Orbits (CCO): comet catalog updated since 1970s
  • compact object (CO): dense astronomical body such as white dwarf or denser
• CCS:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CCSN:
  • core collapse supernova (CCSN): supernova resulting from the collapse of the core of a star
  • supernova progenitor: the star or star system that produces a supernova
• CCSN progenitor:
  • supernova progenitor: the star or star system that produces a supernova
• cD:
  • Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
  • giant elliptical galaxy: very large elliptical galaxy generally at a galaxy cluster's center
• cD galaxy:
  • elliptical galaxy: ellipsoidal-shaped galaxy
  • giant elliptical galaxy: very large elliptical galaxy generally at a galaxy cluster's center
• CDA:
  • Cassini: explorer spacecraft sent to Saturn
• CDF-N:
  • Chandra Deep Field North (CDFN,CDF-N): X-ray deep survey encompassing HDF region
• CDF-North:
  • Chandra Deep Field North (CDFN,CDF-N): X-ray deep survey encompassing HDF region
• CDF-S:
  • Chandra Deep Field South (CDFS,CDF-S): X-ray deep survey encompassing HDF-South region
  • Spitzer Extragalactic Representative Volume Survey (SERVS): infrared survey of some well-studied fields
• CDF-South:
  • Chandra Deep Field South (CDFS,CDF-S): X-ray deep survey encompassing HDF-South region
• CDFN:
  • Chandra Deep Field North (CDFN,CDF-N): X-ray deep survey encompassing HDF region
• CDFS:
  • Chandra Deep Field South (CDFS,CDF-S): X-ray deep survey encompassing HDF-South region
  • FourStar Galaxy Evolution Survey (ZFOURGE,Z-FOURGE): infrared deep-survey to detect galaxies
• CDISORT:
  • DISORT: simulation of radiative transfer in an atmosphere
• CDM:
  • Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
  • cold dark matter (CDM): one of three types of "dark matter" theory
  • dark matter: matter suggested by gravity in galaxies and galaxy clusters
  • fuzzy dark matter (FDM): concept of extremely light dark matter particles
• CDPP:
  • combined differential photometric precision (CDPP): calculated relation of photometric variation to SNR
• CDS:
  • Centre de données astronomiques de Strasbourg (CDS): repository of astronomical data
  • SIMBAD: online database of astronomical objects
  • Solar and Heliospheric Observatory (SOHO): satellite observing the Sun
• CDSCC:
  • NASA Deep Space Network (NASA DSN,DSN): NASA's world-wide radio communication setup
• CE:
  • chemical equilibrium (CE): state where chemical makeup is unchanging
  • post-common envelope binary (PCEB): binary star system showing unusual stellar evolution
• CE1:
  • Cosmic Explorer: concept for a very large LIGO-like GW detector
• CE2:
  • Cosmic Explorer: concept for a very large LIGO-like GW detector
• CEA:
  • CEA Service d'Astrophysique (CEA SAp): French national astrophysics research institute
• CEA SAp:
  • CEA Service d'Astrophysique (CEA SAp): French national astrophysics research institute
• CEA Service d'Astrophysique (CEA SAp): French national astrophysics research institute
• CEAS:
  • cavity-enhanced absorption spectroscopy (CEAS): passing a beam through a gas multiple times to amplify absorption lines
• CEB:
  • common envelope: binary star system surrounded by a single gas cloud
  • post-common envelope binary (PCEB): binary star system showing unusual stellar evolution
• CEBE:
  • common envelope: binary star system surrounded by a single gas cloud
  • post-common envelope binary (PCEB): binary star system showing unusual stellar evolution
• Ced:
  • Cederblad Catalog (Ced): list of bright nebulae
• Cederblad:
  • Cederblad Catalog (Ced): list of bright nebulae
• Cederblad Catalog (Ced): list of bright nebulae
• CEDUNA:
  • Long Baseline Array (LBA): radio interferometer using Australian telescopes
• CEL:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• celestial body:
  • astronomical object: planet, star, galaxy, etc.
• celestial coordinate system: system for specifying position of celestial objects
• celestial coordinates:
  • celestial coordinate system: system for specifying position of celestial objects
• celestial equator: equator-like line around the celestial sphere
• celestial event: generally something happening visible in the sky
• celestial mechanics: study of forces and motion of celestial objects
  • apsis: closest or furthest point in an eccentric orbit
  • corotation resonance (CR): an orbital resonance with the same frequency as the orbit
  • disk: rotating disk-shaped object such as disk galaxy or circumstellar disk
  • eccentricity (e): degree to which an orbit is non-circular
  • Hill stability: planetary orbits which will remain in the same order
  • Kozai mechanism: an effect on an orbit by another, more distant orbiting body
  • Lagrange stability: a quality of some stable orbits
  • Lie transform: type of infinitesimal transform
  • orbital element: parameters describing an orbit
  • orbital period: length of time for an orbiting object to complete one cycle
  • orbital resonance: tendency of orbits of multiple bodies to remain in a simple pattern
  • orbital speed: speed of an orbiting body around the barycenter of a system
  • period derivative: rate of change in the period of an orbit or rotation
  • projected semi-major axis: semi-major axis projected onto line-of-sight or plane of the sky
  • Q factor: measure of oscillator's damping
  • semi-major axis (a): maximum radius of an ellipse
  • synchronous orbit: orbit with angular velocity matching the rotation of the orbited body
• celestial meridian: celestial sphere's meridian passing overhead
  • meridian: circle around the Earth passing through both poles
  • transit: a celestial body passing between another and an observer
• celestial north pole:
  • celestial equator: equator-like line around the celestial sphere
  • celestial pole: point within the celestial sphere aligned with Earth's rotation axis
• celestial object:
  • astronomical object: planet, star, galaxy, etc.
• celestial pole: point within the celestial sphere aligned with Earth's rotation axis
  • celestial equator: equator-like line around the celestial sphere
  • celestial meridian: celestial sphere's meridian passing overhead
• celestial south pole:
  • celestial equator: equator-like line around the celestial sphere
  • celestial pole: point within the celestial sphere aligned with Earth's rotation axis
• celestial sphere: the sky in considered as a sphere surrounding the observer
  • appulse: moment of apparent nearest distance of observed bodies
  • celestial coordinate system: system for specifying position of celestial objects
  • celestial equator: equator-like line around the celestial sphere
  • celestial meridian: celestial sphere's meridian passing overhead
  • celestial pole: point within the celestial sphere aligned with Earth's rotation axis
  • declination (dec): direction coordinate above/below celestial equator
  • ecliptic: path of the Sun on the celestial sphere as seen from Earth
  • ecliptic coordinate system: celestial coordinate system system based upon Earth's orbital plane
  • epoch: when an object was at a particular set of celestial coordinates
  • equatorial coordinate system: latitude/longitude-like system for the celestial sphere
  • equinox: times when tilt of Earth is neither toward or away from the Sun
  • galactic anticenter: direction opposite the galactic center
  • galactic coordinate system (GCS): celestial coordinate system system based upon the galactic plane
  • galactic north: determination of the more northern direction of the Milky Way's axis
  • horizontal coordinate system: celestial coordinate system based upon horizon and north
  • International Celestial Reference System (ICRS): standardized variation of equatorial coordinate system
  • position angle (PA): indication of a direction across the celestial sphere
  • right ascension (RA): direction coordinate along celestial equator
  • solar apex: direction that the Sun is moving compared to nearby stars
  • supergalactic coordinate system: celestial coordinate system system based upon the supergalactic plane
  • zenith: spot on the sky directly above something
• CELIAS:
  • Solar and Heliospheric Observatory (SOHO): satellite observing the Sun
• cell:
  • Hadley cell: circulation pattern of up at the equator, poleward, down, and back
  • zonal flow: east-west air circulation
  • zone: apparent "horizontal" band in an atmosphere
• Celsius:
  • kelvin (K): temperature scale starting at absolute zero
• CELT:
  • California Extremely Large Telescope (CELT): concept for an extremely large telescope
• CEMP:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• CEMP-no:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• CEMP-r:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• CEMP-r/s:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• CEMP-s:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• centaur: asteroid-like body orbiting among the outer planets
  • 10199 Chariklo: largest minor planet in the outer solar system
• Centaur rocket stage:
  • LCROSS: space probe observing the lunar poles
• centaurs:
  • minor planet: lesser solar system body without comet characteristics
• Centaurus:
  • Sloan Great Wall (SGW): large slab of galaxies discovered in SDSS
• Centaurus A:
  • Council of Giants: twelve large galaxies surrounding the Local Group
• Center for Astronomy of Heidelberg University:
  • Institute of Theoretical Astrophysics (ITA): Heidelberg research institute
• Center for Astrophysics (CfA): Harvard and Smithsonian research and education organization
  • CfA Redshift Survey: 1970s-1990s surveys of galaxy redshifts
• Center for Astrophysics Redshift Survey:
  • CfA Redshift Survey: 1970s-1990s surveys of galaxy redshifts
• Center for High Angular Resolution Astronomy:
  • CHARA: optical interferometer
• center of gravity:
  • barycenter: center of mass of two orbiting bodies
• center of mass:
  • barycenter: center of mass of two orbiting bodies
  • reduced mass: the reciprocal of the sum of the reciprocals of the masses of two objects
• center of mass frame of reference:
  • barycenter: center of mass of two orbiting bodies
• center of the Milky Way:
  • galactic center: region at the middle of the Milky Way
• centigrade:
  • kelvin (K): temperature scale starting at absolute zero
• centimeter size barrier:
  • barrier: challenging issue regarding planet formation
• centimeter-gram-second system:
  • CGS: metric system variant
• centimeter-wave astronomy:
  • radio astronomy: astronomy observation and analysis of radio EMR
• central body:
  • primary: central body of a system such as the Sun in the solar system
• central compact object:
  • compact object (CO): dense astronomical body such as white dwarf or denser
• central limit theorem:
  • Gaussian function: function producing the bell curve
• central peak:
  • complex crater: crater with central high-point
• central star of the planetary nebula:
  • planetary nebula (PN): gas shell ejected by a red giant
• Centre de données astronomiques de Strasbourg (CDS): repository of astronomical data
  • SIMBAD: online database of astronomical objects
• Centre national d'ètudes spatiales (CNES): French space agency
• CEP:
  • Cepheid variable (CEP): type of star that varies with a constant period
• Cepheid:
  • Cepheid variable (CEP): type of star that varies with a constant period
• Cepheid variable (CEP): type of star that varies with a constant period
  • pulsating star: variable star that varies through energy pulses
• Ceres: dwarf planet and largest asteroid
  • asteroid: minor planet without comet characteristics
  • Dawn: explorer spacecraft sent to asteroids Vesta and Ceres
  • dwarf planet: round like a planet, only smaller
  • facula: bright spot on a planet or the Sun
  • planet: round object orbiting a star that clears out its own orbital path
  • protoplanet: simplest, least-developed object classified as a planet
  • Titius-Bode law: relationship between the distances between solar system planets
• Cerro Armazones Observatory:
  • European Extremely Large Telescope (E-ELT,ELT): 39-meter telescope under construction
• Cerro Chajnantor:
  • Fred Young Submillimeter Telescope (FYST,CCAT-p): planned 6-meter submillimeter telescope in Chile
  • Llano de Chajnantor Observatory: group of observatories on a high plateau of the Atacama Desert
• Cerro Chajnantor Atacama Telescope:
  • CCAT: 25-meter submillimeter telescope plan for Chile
• Cerro Chajnantor Atacama Telescope, prime:
  • Fred Young Submillimeter Telescope (FYST,CCAT-p): planned 6-meter submillimeter telescope in Chile
• Cerro Pachón:
  • Gemini Observatory: pair of telescopes in Hawaii and Chile
• Cerro Paranal:
  • Paranal Observatory: ESO Atacama observatory with ESO VLT
• Cerro Toco:
  • Llano de Chajnantor Observatory: group of observatories on a high plateau of the Atacama Desert
• Cerro Tololo:
  • All Sky Automated Survey for SuperNovae (ASAS-SN,ASASSN): survey of both hemispheres for supernovae
• Cerro Tololo Inter-American Observatory (CTIO): NOAO observatory in Chile with Blanco telescope
  • Calán/Tololo Survey: late 1980s to early 1990s search to redshift 0.1
  • CTIO Upper-Scorpius OB Association Survey (UScoCTIO): survey of low-mass stars and brown dwarfs
  • Dark Energy Survey (DES): survey aimed at mapping the universe's expansion
  • DECaLS: survey imaging part of SDSS footprint with DECam
  • Deep Lens Survey (DLS): investigating mass distribution of the universe
  • Kitt Peak National Observatory (KPNO): NRAO observatory in Arizona with Mayall telescope
  • Multiwavelength Survey by Yale-Chile (MUSYC): optical/NIR survey of four deep fields
  • National Optical Astronomy Observatory (NOAO): US optical astronomy organization
  • NOAO Deep Wide-field Survey (NDWFS): survey investigating large scale structure of the universe
  • SOAR: 4.1 m reflector telescope in Chile
  • USNO Twin Astrograph: USNO astrograph deployed in 1970
  • Víctor M. Blanco Telescope: 4 m reflector telescope in Chile
• CERTO:
  • ARGOS: 1999 technology-research satellite
• CES:
  • ESO 3.6m Telescope: reflector telescope at La Silla
• CfA:
  • Astrophysics Data System (ADS): website with astrophysics bibliography and paper archive
  • Center for Astrophysics (CfA): Harvard and Smithsonian research and education organization
  • CfA Redshift Survey: 1970s-1990s surveys of galaxy redshifts
• CfA Redshift Survey: 1970s-1990s surveys of galaxy redshifts
  • Great Wall: large slab of galaxies
• CfA1 Survey:
  • CfA Redshift Survey: 1970s-1990s surveys of galaxy redshifts
• CfA2 Great Wall:
  • Great Wall: large slab of galaxies
• CfA2 Survey:
  • CfA Redshift Survey: 1970s-1990s surveys of galaxy redshifts
• CFBD:
  • CFBDS: survey in search of brown dwarfs
• CFBDS: survey in search of brown dwarfs
• CFBDSIR:
  • CFBDS: survey in search of brown dwarfs
• CFD:
  • lattice Boltzmann method (LBM): computational fluid dynamics method treating the fluid as particles
• CFH12k:
  • Canada-France-Hawaii Telescope (CFHT): 3.6 meter optical/infrared telescope in Hawaii
  • Canadian Cluster Comparison Project (CCCP): multi-wavelength survey of fifty X-ray-selected galaxy clusters
• CFHQS:
  • Canada-France High-z Quasar Survey (CFHQS): 2000s distant quasar survey
• CFHT:
  • Canada-France High-z Quasar Survey (CFHQS): 2000s distant quasar survey
  • Canada-France Redshift Survey (CFRS): 1990s survey of galaxies to z = 1 to find associations of redshift to characteristics
  • Canada-France-Hawaii Telescope (CFHT): 3.6 meter optical/infrared telescope in Hawaii
  • Canadian Cluster Comparison Project (CCCP): multi-wavelength survey of fifty X-ray-selected galaxy clusters
  • CFHTLS: surveys of transients and stars
  • Mauna Kea: Hawaiian mountain, the site of observatories
  • Mauna Kea Observatories (MKO): observatories on Mauna Kea in Hawaii
  • Multi-Epoch Nearby Cluster Survey (MENeaCS): Type Ia supernova survey in clusters at z = 0.1
  • Outer Solar System Origins Survey (OSSOS): survey searching for trans-Neptune objects
  • PAndAS: survey of M31 and M33
  • SPIRou: CFHT spectropolarimeter for exoplanet research
  • Supernova Legacy Survey (SNLS): detect and monitor supernovae to measure the effects of dark energy
• CFHTLS: surveys of transients and stars
• CFL condition:
  • finite difference method (FDM): means of estimating calculus and differential equation solutions
• CFRS:
  • Canada-France Redshift Survey (CFRS): 1990s survey of galaxies to z = 1 to find associations of redshift to characteristics
• CFS:
  • Astrographic Catalog (AC): historical star catalog of the whole sky to magnitude 11
• CFT:
  • conformal field theory (CFT): a type of quantum field theory
• CG:
  • barycenter: center of mass of two orbiting bodies
  • Bok globule: dense molecular cloud
  • dwarf galaxy: small galaxy with a few billion stars
• CGB:
  • cosmic background radiation (CBR): electromagnetic radiation coming from every direction
  • cosmic gamma ray background (CGB): gamma-ray radiation seen everywhere
• CGCG:
  • Catalog of Galaxies and Clusters of Galaxies (CGCG): list of galaxies/clusters assembled in 1960s
• CGCS:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CGI:
  • Roman Space Telescope (RST,WFIRST): proposed near-infrared space observatory
• CGM:
  • circumgalactic medium (CGM): gas surrounding a galaxy
• CGO:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CGRO:
  • Compton Gamma Ray Observatory (CGRO,GRO): 1990s space observatory for gamma ray observation
• CGS: metric system variant
  • erg: CGS unit of energy
  • gauss (G,Gs): measurement of magnetic field β
  • magnetic flux (Φ): total magnetism passing through a surface
  • magnetic flux density (B): vector field describing magnetism in relation to the Lorentz force
  • SI: modern metric system
• CGS4:
  • United Kingdom Infrared Telescope (UKIRT): Mauna Kea 3.8 meter infrared telescope
• CGSS:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CH:
  • Canadian Hydrogen Intensity Mapping Experiment (CHIME,CH): radio telescope mapping distant neutral hydrogen
  • methylidyne (CH): compound of one carbon and one hydrogen atom
• CH star:
  • chemically peculiar star (CP star): star with SED showing presence metals unusual for stars
  • methylidyne (CH): compound of one carbon and one hydrogen atom
• CH₃D:
  • methane (CH₄): compound of one carbon and 4 hydrogen atoms
• CH₄:
  • methane (CH₄): compound of one carbon and 4 hydrogen atoms
• Chabrier IMF:
  • initial mass function (IMF): function describing initial mass of stars
• CHAI:
  • CCAT: 25-meter submillimeter telescope plan for Chile
  • Fred Young Submillimeter Telescope (FYST,CCAT-p): planned 6-meter submillimeter telescope in Chile
• Chajnantor Observatory:
  • Llano de Chajnantor Observatory: group of observatories on a high plateau of the Atacama Desert
• Chajnantor Plateau:
  • Llano de Chajnantor Observatory: group of observatories on a high plateau of the Atacama Desert
• Challenger:
  • SPARTAN: series of astronomy satellites launched/retrieved by space shuttle
• Chandler Wobble:
  • photographic zenith tube (PZT): telescope permanently mounted to the zenith
• Chandra:
  • ACIS: imaging spectrometer on Chandra X-ray telescope
  • Chandra Deep Field North (CDFN,CDF-N): X-ray deep survey encompassing HDF region
  • Chandra Deep Field South (CDFS,CDF-S): X-ray deep survey encompassing HDF-South region
  • Chandra X-ray Observatory (CXO): space X-ray telescope
  • Extended Chandra Deep Field-South Survey (ECDFS): 1100 square arcminute X-ray survey
  • GOODS: survey combining data from different sources on very distant objects
• Chandra Carina Complex Project:
  • Canadian Cluster Comparison Project (CCCP): multi-wavelength survey of fifty X-ray-selected galaxy clusters
• Chandra COSMOS Survey:
  • Cosmic Evolution Survey (COSMOS): investigation of dark matter and the universe's large scale structure
• Chandra Deep Field North (CDFN,CDF-N): X-ray deep survey encompassing HDF region
• Chandra Deep Field South (CDFS,CDF-S): X-ray deep survey encompassing HDF-South region
  • Spitzer Extragalactic Representative Volume Survey (SERVS): infrared survey of some well-studied fields
• Chandra Deep Fields:
  • Chandra Deep Field North (CDFN,CDF-N): X-ray deep survey encompassing HDF region
• Chandra X-ray Observatory (CXO): space X-ray telescope
  • ACIS: imaging spectrometer on Chandra X-ray telescope
• Chandrasekhar friction:
  • dynamical friction: drag produced by gravitational interaction with surrounding objects
• Chandrasekhar limit: maximum mass of a white dwarf
• ChaNGa:
  • N-body simulation: simulation of many objects gravitationally-bound to each other
• chaos:
  • Lyapunov time: timescale over which a dynamical system is chaotic
• chaos theory: theory of systems highly sensitive to initial conditions
• CHARA: optical interferometer
  • optical interferometer: interferometer of visible light
• characteristic age:
  • pulsar characteristic age (τ): approximate age determination of a pulsar based upon rotation rate
• characteristic magnetic field:
  • pulsar characteristic age (τ): approximate age determination of a pulsar based upon rotation rate
• characteristic strain:
  • gravitational wave strain (h): a measure of the magnitude of a gravitational wave
• Characterizing Exoplanet Satellite:
  • CHEOPS: space telescope in development to measure radii of exoplanets
• charge:
  • quantum number: number representing a conserved quantity
• charge barrier:
  • barrier: challenging issue regarding planet formation
  • electrostatic barrier: the problem that dust grains will repel and not join to form planet seeds
• charge exchange:
  • atmospheric escape: escape of gas particles from a planet's atmosphere
• charge-coupled device:
  • CCD: electronic device to detect light
  • quantum efficiency (QE): measure of instrument's ability to sense EMR
• charged black hole:
  • black hole model: description of a BH using math or computation
• charged particles:
  • spark chamber: type of ion detector
• Chariklo:
  • 10199 Chariklo: largest minor planet in the outer solar system
• CHARIS:
  • Subaru Telescope: 8.2 meter telescope in Hawaii
• charm quark:
  • particle: very small thing
  • quark: type of elementary particle incorporated in protons and neutrons
  • standard model: model of elementary particles including quarks
• Charon:
  • Earth: third solar system planet from the Sun
  • Haumea: dwarf planet discovered in 2004
  • moon: a planet's natural satellite, such as Earth's
  • Pluto: dwarf planet formerly listed as one of the nine planets
  • synchronous orbit: orbit with angular velocity matching the rotation of the orbited body
• CHE:
  • double star designation: systems and format of double star designators
• ChemCam:
  • Mars Science Laboratory (MSL): mission to Mars with rover
• chemical composition:
  • abundances: relative amounts of each chemical element
• chemical composition of the universe:
  • abundances: relative amounts of each chemical element
• chemical differentiation:
  • atmosphere: gas surrounding astronomical object
• chemical element:
  • element: class of atom based on its number of protons
• chemical equilibrium (CE): state where chemical makeup is unchanging
• chemical evolution:
  • abundances: relative amounts of each chemical element
• chemical kinetics:
  • chemical equilibrium (CE): state where chemical makeup is unchanging
• chemical species:
  • reduction potential (E_h,ORP,pE): measure of a chemical species' tendency to acquire electrons
• chemically peculiar:
  • chemically peculiar star (CP star): star with SED showing presence metals unusual for stars
• chemically peculiar star (CP star): star with SED showing presence metals unusual for stars
• chemisorption:
  • adsorption: adhesion to a surface
• chemistry:
  • abiotic oxygen: oxygen from non-life sources
  • abundances: relative amounts of each chemical element
  • acetylene (C₂H₂): compound of two carbon and two hydrogen atoms
  • acidity (pH): measure of the activity of hydrogen ions in a solution
  • adsorption: adhesion to a surface
  • amine: type of compound containing nitrogen
  • ammonia (NH₃): particular compound of nitrogen and hydrogen
  • atomic number (Z): number of protons in an atomic nucleus
  • Avogadro's number (N_A): roughly number of hydrogen atoms in a gram
  • bulk density: total mass divided by total volume
  • calcium (Ca): element, Ca, atomic number 20
  • carbon (C): element, C, atomic number 6
  • carbon dioxide (CO₂): compound of carbon atom and two oxygen atoms
  • carbon monoxide (CO): compound of carbon and oxygen, one atom each
  • carbonate system: system governing water and CO2 in the presence of each other
  • carbonate-silicate cycle: long-term cycle that sequesters Earth carbon
  • chemical equilibrium (CE): state where chemical makeup is unchanging
  • chemodynamics: study of the dynamics of chemical reactions
  • clathrate: crystal lattice with voids that can trap molecules
  • diffusion: the spreading of particles toward an even distribution
  • electron shell: radius-level around an atomic nucleus at which electrons can orbit
  • element: class of atom based on its number of protons
  • energetic neutral atom (ENA): high-speed neutral atom
  • equilibrium condensation model: chemical model explaining solar system planet abundances
  • ethylene (C₂H₄): compound of two carbon and four hydrogen atoms
  • fractionation: separation of compounds from a mixture
  • fractionation factor: isotope quantity
  • geochemistry: the chemistry of the Earth, planets, and moons
  • glycine (Gly,G): smallest of the twenty common amino acids
  • helium (He): non-metallic element, He, atomic number 2
  • hydrocarbon (HC): any compound of just carbon and hydrogen
  • hydrogen (H): most prominent element, atomic number 1
  • hydrogen deuteride (HD): hydrogen molecule with one deuterium atom
  • hydroxyl (OH): neutral compound of hydrogen and oxygen, one atom each
  • ice: solid state of water
  • iron (Fe): metal, Fe, atomic number 26
  • lithium (Li): metal, Li, atomic number 3
  • magnesium (Mg): element, Mg, atomic number 12
  • metallic hydrogen: a high-pressure state of hydrogen that is conductive
  • methane (CH₄): compound of one carbon and 4 hydrogen atoms
  • methylidyne (CH): compound of one carbon and one hydrogen atom
  • Milky Way chemical evolution: process of the development of metals in the Milky Way
  • mole (mol): unit roughly the count of hydrogen atoms in a gram
  • molecular handedness: mirror-imaged variants of some molecules
  • neon (Ne): element, Ne, atomic number 10
  • nickel (Ni): metal, Ni, atomic number 28
  • nitrite (NO₂^-): ion of a nitrogen atom and two oxygen atoms with extra electron
  • nitrogen (N): metal, N, atomic number 7
  • number density (n): number of objects per volume
  • oxidation state: number of electrons loaned out by an atom in an ionic bond
  • oxygen (O): element, O, atomic number 8
  • PAH emissions: infrared emission from polycyclic aromatic hydrocarbons in gas clouds
  • particle number (N): number of particles
  • photochemistry: study of the chemical effects of light
  • photodissociation: chemical reaction in which photons break chemical bonds
  • polycyclic aromatic hydrocarbon (PAH): hydrocarbons consisting of meshes of benzene rings
  • potassium/thorium ratio (K/Th ratio): indication of thermal history
  • radiolysis: similar to photodissociation from higher energy photons
  • reducing atmosphere: atmosphere lacking oxygen or other oxidizers
  • reduction potential (E_h,ORP,pE): measure of a chemical species' tendency to acquire electrons
  • refractory material: material with high condensation temperature
  • relativistic effect: a substantial fraction of the speed of light
  • siderophile: material that dissolves in molten iron
  • signatures of formation: qualities of a body that suggest how it was formed
  • silicate: type of compound including silicon and oxygen
  • silicate weathering feedback: feedback mechanism stabilizing carbon in Earth atmosphere
  • silicon (Si): metal, Si, atomic number 14
  • sodium (Na): metal, Na, atomic number 11
  • SPECTRE: an interactive spectrum analysis software package
  • stellar population: grouping of stars according to metallicity
  • sulfur (S): metal, S, atomic number 16
  • surface reaction: such as reactions between gas and adjacent liquid
  • titration: analyzing a chemical solution by color change
  • volatile material: material with low condensation temperature
  • water activity (a_w): measure of partial vapor pressure of water
• chemodynamics: study of the dynamics of chemical reactions
• CHEOPS: space telescope in development to measure radii of exoplanets
• Cherenkov cone:
  • Cherenkov radiation: radiation from the shock of a charged particle passing through a medium
• Cherenkov detector: type of high energy photon or particle detector
• Cherenkov gamma-ray telescope:
  • Cherenkov detector: type of high energy photon or particle detector
• Cherenkov radiation: radiation from the shock of a charged particle passing through a medium
  • Cherenkov detector: type of high energy photon or particle detector
• Cherenkov telescope:
  • Cherenkov detector: type of high energy photon or particle detector
• Cherenkov Telescope Array (CTA): ground gamma-ray telescope array in development
• Chereul:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• Chern-Simons general relativity:
  • Chern-Simons gravity: one type of modified general relativity
• Chern-Simons gravity: one type of modified general relativity
• Chern-Simons modified general relativity:
  • Chern-Simons gravity: one type of modified general relativity
• Chern-Simons theory:
  • Chern-Simons gravity: one type of modified general relativity
• Chi Draconis A:
  • F-type star (F): spectral class of star a bit hotter than then Sun
• chi-squared:
  • chi-squared test (χ² test): statistical significance test
• chi-squared test (χ² test): statistical significance test
• Chile:
  • Atacama B-Mode Search (ABS): 2012-2014 survey of the CMB
  • Atacama Cosmology Telescope (ACT): 6 meter microwave survey telescope in Chile
  • Atacama Desert: high altitude, dry plateau in Chile, the site of observatories
  • Atacama Large Millimeter Array (ALMA): large radio telescope array in Chile
  • Atacama Pathfinder Experiment (APEX): 12-meter submillimeter telescope in Chile
  • Atacama Submillimeter Telescope Experiment (ASTE): ten meter submillimeter telescope in Chile
  • AtLAST: plan for submillimeter telescope in Chile
  • BlackGEM: telescope array in development to follow up gravitational wave signals
  • Calán/Tololo Survey: late 1980s to early 1990s search to redshift 0.1
  • CCAT: 25-meter submillimeter telescope plan for Chile
  • Cerro Tololo Inter-American Observatory (CTIO): NOAO observatory in Chile with Blanco telescope
  • Cherenkov Telescope Array (CTA): ground gamma-ray telescope array in development
  • CMB Stage-4 (CMB-S4): planned 2020s-generation of ground CMB observations
  • Cosmic Background Imager (CBI): radio telescope in Chile observing the CMB
  • Dark Energy Survey (DES): survey aimed at mapping the universe's expansion
  • DECaLS: survey imaging part of SDSS footprint with DECam
  • ESO 3.6m Telescope: reflector telescope at La Silla
  • European Extremely Large Telescope (E-ELT,ELT): 39-meter telescope under construction
  • European Southern Observatory Very Large Telescope (ESO VLT,VLT): four 8.2-meter optical telescopes in Chile that can act together
  • Fred Young Submillimeter Telescope (FYST,CCAT-p): planned 6-meter submillimeter telescope in Chile
  • Giant Magellan Telescope (GMT): 24.5 meter telescope under construction
  • HARPS: high-precision spectrograph for exoplanet searches
  • La Silla Observatory (LSO): Atacama-desert observatory run by ESO
  • La Silla Paranal Observatory (LPO): manages three ESO observatory sites in Chile
  • Las Campanas Observatory (LCO): observatory in southern Atacama Desert
  • Llano de Chajnantor Observatory: group of observatories on a high plateau of the Atacama Desert
  • Magellan Telescopes: pair of 6.5 m optical telescopes in Chile
  • Magellanic Clouds Photometric Survey (MCPS): UBVI survey of the Magellanic Clouds
  • NANTEN2: millimeter telescope in Chile
  • New Technology Telescope (NTT): 3.58-meter reflector telescope in Chile
  • NGTS: survey of transits from Chile
  • NIRPS: near-infrared extension to HARPS spectrograph
  • Paranal Observatory: ESO Atacama observatory with ESO VLT
  • POLARBEAR: instrument to map CMB polarization
  • QUIET: survey to measure the polarization of the CMB
  • Rubin Observatory (VRO,LSST): 8-meter survey reflector telescope under construction in Chile
  • Simons Observatory (SO): CMB observatory on Atacama Desert
  • SOAR: 4.1 m reflector telescope in Chile
  • SPECULOOS: search for Earth-like exoplanets orbiting nearby dim stars
  • Swedish-ESO Submillimetre Telescope (SEST): former 15 m radio telescope array in Chile
  • Swope Supernova Survey (SSS): survey of low-redshift Type Ia SN light curves
  • TRAPPIST: ground-based automatic transiting planet finding telescope
  • University of Tokyo Atacama Observatory (TAO): observatory for a 6.5 m infrared telescope under construction
  • Víctor M. Blanco Telescope: 4 m reflector telescope in Chile
  • VISTA: 4.1 meter telescope in Paranal Observatory in Chile
  • VLT Survey Telescope (VST): survey telescope located at the VLT site
• CHIME:
  • Canadian Hydrogen Intensity Mapping Experiment (CHIME,CH): radio telescope mapping distant neutral hydrogen
  • Dominion Radio Astrophysical Observatory (DRAO): radio observatory in British Columbia, Canada
• CHIMERA:
  • atmospheric model: model to describe or simulate a planet's atmosphere
  • Hale Telescope: 5.1 m reflector telescope in California
• China:
  • ARGO-YBJ Experiment: cosmic-ray/gamma-ray detector in Tibet
  • FAST: Arecibo-like 500 m telescope in deployment in China
  • LAMOST: Chinese telescope for spectroscopic surveys of stars and galaxies
  • Tianwen-1 (TW-1): Mars rover launched in July 2020 and on its way
• CHIP:
  • High Altitude Observatory (HAO): NCAR unit observing and monitoring the Sun
• CHIPSat: small satellite to investigate ISM plasma
• chiral EFT:
  • effective field theory (EFT): type of useful simplification of a field theory
• chirality:
  • molecular handedness: mirror-imaged variants of some molecules
• chirp: burst of signal rising or falling in frequency
• chirp mass (M_c,ℳ): a reduced-mass-like quantity that relates to gravitational waves
• chloride:
  • geochemistry: the chemistry of the Earth, planets, and moons
• chlorine:
  • geochemistry: the chemistry of the Earth, planets, and moons
• chondrite: stony meteorites showing no melting
• chondrule:
  • CAI: calcium/aluminum specs in chondrites
  • chondrite: stony meteorites showing no melting
• chopper:
  • chopping mirror: internal pivoting mirror to slightly change the instrument's aim
• chopping:
  • chopping mirror: internal pivoting mirror to slightly change the instrument's aim
• chopping mirror: internal pivoting mirror to slightly change the instrument's aim
• CHORD:
  • Canadian Hydrogen Intensity Mapping Experiment (CHIME,CH): radio telescope mapping distant neutral hydrogen
• Christie:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• ChroMag:
  • Coronal Solar Magnetism Observatory (COSMO): proposed solar observatory
• chromatic aberration: focusing different wavelengths differently
  • aberration: types of flaws in telescope images
• chromatic dispersion:
  • velocity dispersion (σ): statistical dispersion of velocities of a group of objects
• chromium:
  • Ap star: peculiar type of A star
• chromosphere: middle layer of the Sun's atmosphere
  • Moreton wave: type of wave moving across the chromosphere
  • stellar atmosphere: photosphere and above
  • Sun surface features: features on the Sun's surface
• chromospheric activity index: measure of magnetic activity of a star's chromosphere
• Chthonian:
  • atmospheric escape: escape of gas particles from a planet's atmosphere
• Chthonian planet:
  • atmospheric escape: escape of gas particles from a planet's atmosphere
• Chupina:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CHZ:
  • habitable zone (HZ): zone where conditions are favorable for life
• CI:
  • carbon (C): element, C, atomic number 6
  • rare designator prefixes: designator prefixes generally used for only a few objects
  • state of ionization: difference in an ion's electron count versus proton count
• CIAO:
  • Subaru Telescope: 8.2 meter telescope in Hawaii
• CIB:
  • cosmic background radiation (CBR): electromagnetic radiation coming from every direction
  • cosmic infrared background (CIB,CIBR): widespread infrared radiation not associated with known sources
  • PEP: survey aimed at early star formation
• CIBR:
  • cosmic infrared background (CIB,CIBR): widespread infrared radiation not associated with known sources
• CID:
  • Cosmic Evolution Survey (COSMOS): investigation of dark matter and the universe's large scale structure
• CIDA:
  • Stardust: space mission that collected and returned comet coma dust
• CIG: initiative to produce Earth-science software
• Cigar Galaxy:
  • M82: nearby starburst galaxy
• CII:
  • carbon (C): element, C, atomic number 6
  • state of ionization: difference in an ion's electron count versus proton count
• CIII:
  • state of ionization: difference in an ion's electron count versus proton count
• Cimolai:
  • ACe consortium: corporations contracted to construct E-ELT
• CINEOS:
  • Campo Imperatore Near-Earth Object Survey (CINEOS): survey of near-Earth objects
• CIO:
  • Catalog of Infrared Observations (CIO): collection of infrared observation data from numerous sources
• CIRCE:
  • Gran Telescopio Canarias (GTC): 10.4 meter telescope in the Canary Islands
• Circinus Galaxy (ESO 97-G13): nearest Seyfert galaxy
• circle:
  • conic section: orbit shapes, like the intersection of a plane and cone
• circle of latitude: circle around the Earth of points equidistant from a pole or the equator
• circular polarization:
  • circular polarization ratio (CPR): ratio of circular polarization handedness in reflected radar signal
  • polarization: property of waves that oscillate in a particular direction
• circular polarization radar:
  • circular polarization ratio (CPR): ratio of circular polarization handedness in reflected radar signal
• circular polarization ratio (CPR): ratio of circular polarization handedness in reflected radar signal
• circumbinary planet: exoplanet orbiting two stars
• circumgalactic medium (CGM): gas surrounding a galaxy
• circumplanetary disk: disk of dust and gas around a planet
• circumstellar disk: disk or ring shaped accumulation of matter around a star
  • disk: rotating disk-shaped object such as disk galaxy or circumstellar disk
• circumstellar envelope:
  • asymptotic giant branch (AGB): a second stage of helium burning in some stars
  • planetary nebula (PN): gas shell ejected by a red giant
• circumstellar habitable zone:
  • habitable zone (HZ): zone where conditions are favorable for life
• circumstellar material:
  • superluminous supernova (SLSN): stellar explosion larger than a supernova
• cirrus:
  • infrared cirrus: cirrus-cloud-like infrared emissions from dust, etc.
• cirrus cloud:
  • infrared cirrus: cirrus-cloud-like infrared emissions from dust, etc.
• CIRS:
  • Cassini: explorer spacecraft sent to Saturn
  • CEA Service d'Astrophysique (CEA SAp): French national astrophysics research institute
• CISCO:
  • Subaru Telescope: 8.2 meter telescope in Hawaii
• CITA:
  • Canadian Institute for Theoretical Astrophysics (CITA,ICAT): national research organization at University of Toronto
• CIV:
  • ARGOS: 1999 technology-research satellite
• CIVA:
  • Rosetta: space probe that visited a comet
• CKM Matrix:
  • quantum mixing: means by which one particle spontaneously changes to another
• CKM Mixing:
  • quantum mixing: means by which one particle spontaneously changes to another
• CKS:
  • California-Kepler Survey (CKS): followup to Kepler to determine stellar radii
• CKS-COOL:
  • California-Kepler Survey (CKS): followup to Kepler to determine stellar radii
• Cl:
  • galaxy cluster (CL): large group of galaxies gravitationally-bound to the group
  • globular cluster (GC): spherical group of stars orbiting a galaxy
• CLAES:
  • Upper Atmosphere Research Satellite (UARS): 1990s spacecraft to observe Earth ozone layer
• CLASS:
  • Cosmic Lens All-sky Survey (CLASS): radio survey aimed at gravitational lenses
  • CRATES: catalog of 8.4 GHz data on radio sources
• Class 0 YSO:
  • young stellar object (YSO): early stage of a star
• Class I YSO:
  • young stellar object (YSO): early stage of a star
• Class II YSO:
  • young stellar object (YSO): early stage of a star
• Class III YSO:
  • young stellar object (YSO): early stage of a star
• classical Cepheid:
  • Cepheid variable (CEP): type of star that varies with a constant period
• classical gravitational field:
  • gravitational field: gravitational force as distributed over a space
• classical KBO:
  • Kuiper Belt (K Belt,KB): further part of solar system beyond Neptune
• classical Kuiper Belt object:
  • Kuiper Belt (K Belt,KB): further part of solar system beyond Neptune
• classical Lyot coronagraph:
  • Lyot coronagraph (CLC): original coronagraph design
• classical mechanics:
  • quantum field theory (QFT): reworking of quantum mechanics incorporating fields
  • quantum mechanics (QM): modern mechanical theory of small things, on the scale of atoms
  • statistical mechanics: mechanical behavior based upon probability
• classical nova:
  • nova (N): white dwarf explosion
• classical T-Tauri star:
  • T-Tauri star (TTS): type of variable pre-main-sequence star
• classification:
  • dwarf galaxy classification: terms for of dwarf galaxy types
  • Fanaroff-Riley classification: a classification of the radio characteristics of radio sources
  • galaxy classification: morphological classification of galaxies
  • luminosity class: classification of size/luminosity of stars
  • Morgan classification: classification of galaxies by stellar spectrum and morphology
  • planet type: classification of a planet regarding some criteria
  • spectral class: overall classification of stars based upon spectral features
  • spectral type: classification of stars based upon spectral features
  • van den Bergh galaxy classification: galaxy classification variant including luminosity
• clathrate: crystal lattice with voids that can trap molecules
• clathrate hydrate:
  • clathrate: crystal lattice with voids that can trap molecules
• Clay Telescope:
  • Magellan Telescopes: pair of 6.5 m optical telescopes in Chile
• CLC:
  • Lyot coronagraph (CLC): original coronagraph design
• CLEAN: algorithm to extract usable images from interferometry-produced images
  • CASA: software package for radio interferometry image generation
  • dirty image: image that includes the distortions of the beam and sampling
• clean image:
  • CLEAN: algorithm to extract usable images from interferometry-produced images
  • dirty image: image that includes the distortions of the beam and sampling
• clearing the neighborhood:
  • dwarf planet: round like a planet, only smaller
  • planet: round object orbiting a star that clears out its own orbital path
• CLF:
  • conditional luminosity function (CLF): function characterizing luminosity of galaxies with a given halo mass
• climate:
  • autoconversion rate: rate at which water changes from cloud droplets to new raindrops
  • general circulation model (GCM): climate model of a planet's atmosphere or ocean
  • HITRAN: spectroscopic parameters for modeling atmospheric optics
  • MarsWRF: Mars-oriented general circulation model
  • MITgcm: well-known general circulation model
  • one dimensional climate model: atmospheric model ignoring all horizontal motion
  • radiative forcing (RF): difference between a planet's incoming and outgoing radiation
  • ROCKE-3D: Rocky-planet-oriented general circulation model
• climate change:
  • earthshine: reflected and emitted electromagnetic radiation from Earth
• climate model:
  • atmosphere: gas surrounding astronomical object
• Clio2:
  • MMT: 6.5 meter telescope at Mt. Hopkins, Arizona
• close binary:
  • contact binary: binary stars orbiting so close they are touching
• close binary star:
  • binary star: system of two stars co-orbiting
  • black hole merger: two black holes meeting and forming one
• closed magnetic field lines:
  • curvature radiation: synchrotron-like radiation when particles follow curved field lines
• closed universe:
  • critical density (ρ_c): density of the universe which leaves it flat
• closure phase:
  • speckle masking: speckle suppression technique using a calculation of the bispectrum
• cloud: higher-density region of space
  • galaxy cloud: substructure of a supercluster
  • interstellar medium (ISM): matter within a galaxy between star systems
  • Magellanic Bridge: hydrogen cloud joining the Magellanic Clouds
  • Magellanic Stream: series of high-velocity clouds associated with the Magellanic Clouds
  • Orion Molecular Cloud Complex: group of molecular clouds with star forming regions
  • Rho Ophiuchi Cloud Complex: nebula that is a nearby star-forming region
  • Serpens Cloud: molecular cloud with SF regions
  • Smith Cloud: high-velocity cloud on collision course with Milky Way
  • Taurus Molecular Cloud 1 (TMC-1): nearby star-forming region
  • W51: cloud complex radio source
• cloud droplet:
  • autoconversion rate: rate at which water changes from cloud droplets to new raindrops
• cloud fragmentation: clumping in clouds due to gravitational instability
• cloud mass function:
  • dense core mass function (DCMF,CMF): function describing range of masses of dense cores
• cloud of galaxies:
  • galaxy cloud: substructure of a supercluster
• cloud type:
  • Bok globule: dense molecular cloud
  • dark nebula: cloud that obscures stars behind it
  • dense core: dense molecular cloud
  • emission nebula: nebula that emits light such as an HII region or PN
  • evaporating gas globule (EGG): very small dense cloud of hydrogen and dust
  • filament: linear volume of high molecular gas density within a galaxy
  • giant molecular cloud (GMC): interstellar gas cloud with molecules, thousands of solar masses
  • HI region (HI): cloud of neutral atomic hydrogen
  • high-velocity cloud (HVC): fast-moving clouds in galactic halos
  • HII region (HII): cloud of partially-ionized atomic hydrogen
  • infrared dark cloud (IRDC): molecular cloud not emitting nor transmitting infrared
  • molecular cloud: interstellar gas cloud that includes molecules
  • nebula: cloud of dust and gas
  • photodissociation region (PDR): cloud of partially-ionized atomic hydrogen
  • planetary nebula (PN): gas shell ejected by a red giant
  • protogalaxy: gas cloud forming a galaxy
  • radio relics: clouds from past galaxy emitting radio synchrotron radiation
  • reflection nebula: nebula made visible by light it scatters from nearby stars
  • star-forming region (SFR): areas forming stars or ripe for star formation
• clouds:
  • broad emission line region: region within an AGN with broad emission lines
  • carbon monoxide (CO): compound of carbon and oxygen, one atom each
  • cloud fragmentation: clumping in clouds due to gravitational instability
  • dense core mass function (DCMF,CMF): function describing range of masses of dense cores
  • Dickel-Wendker-Bieritz Catalog (DWB): list of HII regions in the Cygnus X star forming region
  • hydrogen deuteride (HD): hydrogen molecule with one deuterium atom
  • hydroxyl (OH): neutral compound of hydrogen and oxygen, one atom each
  • infrared cirrus: cirrus-cloud-like infrared emissions from dust, etc.
  • interstellar astrophysics: astronomy of the ISM including dust and clouds
  • ionization correction factor (ICF): relations between ion abundances and element abundances
  • Jeans length: critical radius below which gravity will collapse a cloud
  • kinematic distance: distance to objects within Milky Way based on radial velocity
  • Lockman hole: region of sky with little Milky-Way neutral hydrogen
  • molecular cloud turbulence: observed turbulence in molecular clouds
  • molecular hydrogen dissociation front (H₂ dissociation front): point in a gas cloud where it is hot enough to dissociate hydrogen
  • pulsar wind nebula (PWN): type of nebula generated by a young pulsar
  • Sharpless Catalog (Sh2): catalog of HII regions found on Palomar plates
  • Strömgren sphere: sphere of ionized hydrogen around an OB star
  • striae: parallel ridges
  • The H2O Southern Galactic Plane Survey (HOPS): survey of molecular clouds in the galactic plane
  • tracer: chemical whose presence indicates the presence of another chemical
  • virial parameter: calculated quantity showing whether a cloud is gravitationally bound
• Cloudy: code to model the effect of gas and plasma on spectra
• clump:
  • dense core mass function (DCMF,CMF): function describing range of masses of dense cores
• clump giant:
  • red clump (RC): like horizontal branch but at one temperature
• clump mass function:
  • dense core mass function (DCMF,CMF): function describing range of masses of dense cores
• CLUPI:
  • Rosalind Franklin: Mars rover in development for 2020 launch
• CLUST:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• cluster:
  • galaxy cluster (CL): large group of galaxies gravitationally-bound to the group
• cluster dark matter halo:
  • dark matter halo: hypothetical dark matter throughout and surrounding a galaxy
• cluster environment:
  • galaxy environment: density and character of galaxies surroundings
• cluster fitting:
  • main sequence fitting: cluster star distance determined through fitting with the H-R diagram
• cluster radius: radius of a galaxy cluster
• CM:
  • barycenter: center of mass of two orbiting bodies
  • color-magnitude diagram (CMD,CM): graph plotting stars' color to luminosity
• CMA:
  • cold mass accretion (CMA): stellar accretion through an accretion disk
• CMa Dwarf:
  • Canis Major Dwarf Galaxy: small irregular galaxy in the Local Group
• CMa Overdensity:
  • Canis Major Dwarf Galaxy: small irregular galaxy in the Local Group
• CMB:
  • angular power spectrum: method of characterizing the CMB
  • anisotropy: directional-dependence such as temperature variation around the CMB
  • Archeops: balloon-borne 1.8 m submillimeter telescope
  • Atacama B-Mode Search (ABS): 2012-2014 survey of the CMB
  • Atacama Cosmology Telescope (ACT): 6 meter microwave survey telescope in Chile
  • BICEP2: survey to measure the polarization of the CMB
  • BOOMERanG: 1990s-2000s balloon-borne 1.3-meter millimeter telescope
  • CAPMAP: early 2000s array that surveyed CMB polarization
  • CMB anisotropies: variations in the spectrum of the CMB
  • CMB lensing: gravitational lensing of the CMB
  • CMB polarization: effects of scattering and lensing on the CMB
  • CMB Stage-4 (CMB-S4): planned 2020s-generation of ground CMB observations
  • CMBFAST: software to calculate CMB anisotropies
  • cold spot: unusually colder spot in the CMB
  • Cosmic Anisotropy Telescope (CAT): 1990s interferometer to measure CMB variations
  • Cosmic Background Explorer (COBE): 1989 satellite for observing the CMB
  • Cosmic Background Imager (CBI): radio telescope in Chile observing the CMB
  • cosmic background radiation (CBR): electromagnetic radiation coming from every direction
  • cosmic microwave background (CMB,CMBR,CBR,MBR): microwave radiation coming from every direction
  • cosmic variance: density variation on a cosmic scale
  • COSMOSOMAS: microwave survey
  • destriping: removing streak-like noise from images
  • diffusion damping: a damping process within the plasma during recombination
  • EBEX: balloon-based CMB polarization survey
  • inflation: theorized rapid expansion of the very early universe
  • initial fluctuations: early universe density variations leading to current universe
  • LiteBIRD: planned spacecraft to map CMB polarization
  • LSPE-STRIP: CMB survey telescope in Canary Islands
  • LSPE-SWIPE: plan for a balloon-based CMB polarization survey
  • MAXIMA: 1998-1999 balloon-borne 1.3-meter millimeter telescope
  • multipole expansion: series expansion of a function over the surface of a sphere
  • Planck: microwave telescope in space
  • POLARBEAR: instrument to map CMB polarization
  • primordial gravitational waves: gravitational waves formed in the early universe
  • QMAP: mid 1990s balloon-based CMB survey
  • QUaD: survey to measure the polarization of the CMB
  • QUBIC: survey to measure the polarization of the CMB
  • QUIET: survey to measure the polarization of the CMB
  • QUIJOTE: survey to measure the polarization of the CMB
  • recombination: time when the universe's ionized hydrogen atoms neutralized
  • reheating: theorized increase in temperature after cosmological inflation
  • RELIKT-1: instrument on 1980s Soviet satellite to view the CMB
  • Sachs-Wolfe effect (SWE,SWeffect): gravitational redshift of the CMB
  • Saskatoon: 1990s survey to measure CMB anisotropy
  • South Pole Telescope (SPT): a microwave to radio telescope at South Pole
  • SPIDER: 2015 balloon-borne observatory to observe CMB polarization
  • Sunyaev-Zel'dovich Array (SZA): array of eight 3.5 meter microwave telescopes
  • Sunyaev-Zel'dovich effect (SZ effect,SZ,SZE): type of distortion of the CMB
  • surface of last scattering: sphere around us from which CMB photons are just reaching us
  • Tenerife Experiment: 1980s-1990s survey of CMB anisotropies
  • time-ordered data (TOD): observation data arranged by the time it was received
  • TopHat: 2001 balloon -based CMB survey
  • Very Small Array (VSA): radio interferometer in Canary Islands
  • Wilkinson Microwave Anisotropy Probe (WMAP): spacecraft that measured variations in the cosmic background radiation
  • Yuan-Tseh Lee Array (YTLA,AMiBA): microwave interferometer in Canary Islands
  • Zel'dovich approximation: model of the formation of cosmological structure
• CMB anisotropies: variations in the spectrum of the CMB
  • baryon acoustic oscillations (BAO): density fluctuations stemming from acoustic waves in the early universe
  • primordial gravitational waves: gravitational waves formed in the early universe
• CMB cold spot:
  • cold spot: unusually colder spot in the CMB
• CMB dipole:
  • CMB anisotropies: variations in the spectrum of the CMB
• CMB foreground:
  • C-BASS: 6 cm survey of the entire sky
  • cosmic microwave background (CMB,CMBR,CBR,MBR): microwave radiation coming from every direction
• CMB halo weak lensing:
  • weak lensing (WL): slight lensing detected in random patterns of distant objects
• CMB lensing: gravitational lensing of the CMB
• CMB polarization: effects of scattering and lensing on the CMB
• CMB Stage-4 (CMB-S4): planned 2020s-generation of ground CMB observations
• CMB-S4:
  • CMB Stage-4 (CMB-S4): planned 2020s-generation of ground CMB observations
• CMBFAST: software to calculate CMB anisotropies
• CMBR:
  • cosmic microwave background (CMB,CMBR,CBR,MBR): microwave radiation coming from every direction
• CMC:
  • Carlsberg Meridian Catalogue (CMC): series of astrometric catalogs from 19th century on
• CMD:
  • color-magnitude diagram (CMD,CM): graph plotting stars' color to luminosity
• CMDM:
  • MMX: Japanese probe to bring back a sample of a Martian moon
• CME:
  • coronal mass ejection (CME): mass of plasma ejected from the Sun
  • ejection: forcing or throwing something out
  • Forbush decrease: decrease in cosmic rays after a coronal mass ejection
  • solar particle event (SPE): episode of higher velocity solar wind
  • Sun surface features: features on the Sun's surface
• CMF:
  • conditional stellar mass function (CSMF): function characterizing galaxies within a halo of a given mass
  • dense core mass function (DCMF,CMF): function describing range of masses of dense cores
• CMFGEN: RT code designed to handle significant stellar wind
• Cn:
  • New General Catalogue (NGC): 1888 catalog of galaxies, star clusters, and other nebulae
  • nova (N): white dwarf explosion
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CN Leonis:
  • Wolf 359: nearby red dwarf
• CNB:
  • cosmic background radiation (CBR): electromagnetic radiation coming from every direction
• CNES:
  • Centre national d'ètudes spatiales (CNES): French space agency
  • COROT: observatory-satellite to look for transiting exoplanets and stellar oscillations
• CNM:
  • HI region (HI): cloud of neutral atomic hydrogen
  • interstellar medium (ISM): matter within a galaxy between star systems
• CNN:
  • convolutional neural network (CNN): type of image processing software
• CNO:
  • CNO cycle: fusion reaction chain turning hydrogen and nitrogen into helium and nitrogen
• CNO cycle: fusion reaction chain turning hydrogen and nitrogen into helium and nitrogen
  • oxygen (O): element, O, atomic number 8
• CNRS:
  • Astronet: European astronomy consortium
• CO:
  • AIM-CO: survey of CO from star forming epoch
  • alpha CO (α_CO): ratio of CO emissions to H₂
  • carbon monoxide (CO): compound of carbon and oxygen, one atom each
  • CARMA EDGE: CO survey of galaxies
  • CO to H₂ factor (Xco,X_CO): assumed ratio between observed CO emission lines and H₂ mass
  • COLD GASS: survey of CO in nearby large galaxies
  • COMAP: high frequency radio telescope to map CO
  • compact object (CO): dense astronomical body such as white dwarf or denser
  • COPSS: survey of CO from star forming epoch
  • Millimeter-wave Intensity Mapping Experiment (mmIME): project to map CO an [CII]
  • PAWS: survey of GMCs in M51a
  • PHIBSS: survey of CO in distant galaxies
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CO ice line:
  • snow line: distance from protostar cool enough for water to condense
• CO J ladder:
  • carbon monoxide (CO): compound of carbon and oxygen, one atom each
• CO ladder:
  • carbon monoxide (CO): compound of carbon and oxygen, one atom each
• CO Legacy Database for GASS:
  • COLD GASS: survey of CO in nearby large galaxies
• CO Mapping Array Pathfinder:
  • COMAP: high frequency radio telescope to map CO
• CO rotational ladder:
  • carbon monoxide (CO): compound of carbon and oxygen, one atom each
• CO to H₂ factor (Xco,X_CO): assumed ratio between observed CO emission lines and H₂ mass
• CO₂:
  • carbon dioxide (CO₂): compound of carbon atom and two oxygen atoms
• CO₂ ice line:
  • snow line: distance from protostar cool enough for water to condense
• COAST: optical interferometer in England
  • Australian Square Kilometre Array Pathfinder (ASKAP): radio telescope array of 36 12-meter dishes
  • optical interferometer: interferometer of visible light
• coastal Kelvin wave:
  • Kelvin waves: pressure and gravity waves formed by Coriolis force and a barrier
• COB:
  • cosmic optical background (COB): widespread optical radiation not associated with known sources
• COBE:
  • Cosmic Background Explorer (COBE): 1989 satellite for observing the CMB
• CoD:
  • Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
• code: astrophysical modeling computer program
  • AREPO: cosmology simulation using moving mesh technique
  • AstroBEAR: MHD simulation system
  • Athena: MHD code
  • ATLAS Stellar Model: computer model of a stellar photosphere
  • BPASS: evolution and population synthesis code for binary stars
  • BT-Settl: model atmosphere of small stars and brown dwarfs
  • Castro: hydrodynamics simulation software
  • Cloudy: code to model the effect of gas and plasma on spectra
  • CMFGEN: RT code designed to handle significant stellar wind
  • COMPAS: SPS code for compact object binaries
  • DISORT: simulation of radiative transfer in an atmosphere
  • DustEM: code to calculate dust extinction and emission
  • Enzo: hydrodynamic simulation system
  • FLASH: hydrodynamic simulation system
  • FORNAX: hydrodynamics simulation software
  • GR1D: core collapse supernova simulation in 1D with GR
  • Hyperion: Monte Carlo radiative transfer code
  • iSALE: code modeling the shock physics of impacts
  • MagIC: numerical code to for fluid dynamics including dynamos
  • mlmapper: software for maximum-likelihood mapmaking
  • NBODY: code to carry out N-body simulations
  • PHOENIX stellar model: computer model of a stellar photosphere
  • PLUTO Code: fluid-dynamic simulation code
  • PROMETHEUS/VERTEX: hydrodynamic simulation system
  • RAMSES: hydrodynamic simulation system
  • RODEO: code for 2D disk simulation
  • SpEC: code to solve general relativity problems
  • StarTrack: stellar population synthesis code
  • Turtlebeach: radiative transfer code
• Code for Anisotropies in the Microwave Background:
  • CMBFAST: software to calculate CMB anisotropies
• code type:
  • cosmological simulation: simulation of the history of the universe
  • N-body simulation: simulation of many objects gravitationally-bound to each other
  • stellar population synthesis code: software to perform stellar population synthesis
• CODEX:
  • European Extremely Large Telescope (E-ELT,ELT): 39-meter telescope under construction
• coefficient:
  • absorption coefficient: measure of how much light a substance absorbs
  • J₂: geopotential coefficient regarding a planet's oblateness
• coeval: the same age
• coherence:
  • coherent light: beam of light at a single frequency
• coherent dense core:
  • dense core: dense molecular cloud
• coherent light: beam of light at a single frequency
• COHSI:
  • United Kingdom Infrared Telescope (UKIRT): Mauna Kea 3.8 meter infrared telescope
• Col:
  • Collinder Catalog (Cr): 1930s catalog of 471 open clusters
• cold dark matter (CDM): one of three types of "dark matter" theory
  • dark matter: matter suggested by gravity in galaxies and galaxy clusters
  • fuzzy dark matter (FDM): concept of extremely light dark matter particles
• cold gas: gas cool enough to form galaxies and stars
  • galaxy strangulation: galaxy star formation stopped by a lack of incoming gas
• COLD GASS: survey of CO in nearby large galaxies
• cold mass accretion (CMA): stellar accretion through an accretion disk
• cold neutral medium:
  • HI region (HI): cloud of neutral atomic hydrogen
  • interstellar medium (ISM): matter within a galaxy between star systems
• cold pixel:
  • hot pixel: CCD pixel that shows more brightness than it should
• cold spot: unusually colder spot in the CMB
• cold start:
  • giant planet formation: process by which giant planets form
  • planet formation: process by which planets form
• cold trap: layer of atmosphere that prevents a gas from escaping by freezing it
• collapsar: neutron star or stellar black hole
• collapsar model:
  • collapsar: neutron star or stellar black hole
  • superluminous supernova (SLSN): stellar explosion larger than a supernova
• collecting area: cross-sectional area over which a telescope receives EMR
  • spectral flux density (S): flux or power of radiation per unit area per unit wavelength
• colliding-wind binary:
  • WR 140: Wolf-Rayet star that produces much dust
• collimate:
  • collimator: device to align beams of light
• collimated light:
  • collimator: device to align beams of light
• collimator: device to align beams of light
• Collinder:
  • Collinder Catalog (Cr): 1930s catalog of 471 open clusters
• Collinder 50:
  • Hyades Cluster: nearest open cluster
• Collinder Catalog (Cr): 1930s catalog of 471 open clusters
• collision:
  • galaxy merger: combination of galaxies upon collision
  • heating: increasing the velocity of particles
• collision cross section:
  • cross section: "area" representation of probability of an interaction of particles
• collisional:
  • globular cluster (GC): spherical group of stars orbiting a galaxy
  • stellar dynamics: stars' gravitational interaction
• collisional broadening:
  • line broadening: processes causing a spectral line to have width
• collisional erosion: removing a body's substance through impacts
• collisionless Boltzmann equation:
  • Vlasov-Poisson equation: equation describing plasma ignoring the magnetic field
• color:
  • color index: a number that characterizes the color of an object
  • color-color diagram (CCD): means of comparing characteristics of stars
  • color-magnitude diagram (CMD,CM): graph plotting stars' color to luminosity
  • color-period diagram: means of comparing periods of stars at various wavelengths
  • cross dispersion spectrograph: echelle spectrograph with additional disperser crosswise to the first
  • imaging Fourier transform spectroscopy (IFTS): Michelson-interferometer-based imaging spectroscopy
  • imaging spectrometer: device to capture spectrum point-by-point of an image
  • integral field spectrograph: spectrograph that captures images
  • integral field unit (IFU): instrument to allow a spectrograph to capture data over a 2D field
  • JHK photometric system (JHK): system to classify stars according to near-infrared colors
  • multi-object spectrograph: device to record the spectrum of multiple targets simultaneously
  • passband: range of electromagnetic wavelengths that a filter allows
  • photometric system: specification of a set of filters/passbands
  • quark matter (QM): matter not made of protons and neutrons but of quarks
  • sensitivity function (S): function of wavelength giving the sensitivity of an instrument
  • spectrograph: device to record the spectrum of incoming light
  • spectrography: charting the strengths of different electromagnetic wavelengths
  • spectrometer: device to measure light by wavelength across its spectrum
  • spectrometry: measuring the strengths of different electromagnetic wavelengths
  • spectroscope: device to study the spectrum of incoming light
  • spectroscopy: measurement of light with various electromagnetic wavelengths
  • Strömgren photometric system: four-color photometric system devised in 1950s
  • UBV photometric system: commonly-cited photometric system for describing stars' colors
• color excess:
  • color index: a number that characterizes the color of an object
  • reddening: red appearance of astronomical objects because blue light is attenuated by dust
• color index: a number that characterizes the color of an object
• color temperature (T_C): temperature-measure of a source based on a color index
  • effective temperature (T_eff,Teff): temperature of an equivalent black body in terms of total radiation
  • temperature: measure of hotness/coldness of matter
• color-color diagram (CCD): means of comparing characteristics of stars
• color-magnitude diagram (CMD,CM): graph plotting stars' color to luminosity
• color-period diagram: means of comparing periods of stars at various wavelengths
• Colossus Telescope: concept for a 50-meter telescope using interferometry
• column density: measure of the matter through which EMR is passing
  • particle number (N): number of particles
• column mass density:
  • column density: measure of the matter through which EMR is passing
• column number density:
  • column density: measure of the matter through which EMR is passing
• Coma:
  • Carbon Monoxide Mapping Array (COMA): planned experiment to observe epoch of reionization
  • coma: aberration where points of light show a tail
  • comet: Sun-orbiting object with coma and possible tail
  • Stardust: space mission that collected and returned comet coma dust
• Coma Berenices:
  • Milky Way subgroup: the Milky Way and its satellites
• Coma Cluster:
  • Coma Supercluster: nearby supercluster
  • galaxy cluster (CL): large group of galaxies gravitationally-bound to the group
• Coma Filament:
  • galaxy filament: thread-like formations of galaxies, 50 to 80 megaparsecs
• Coma Supercluster: nearby supercluster
  • Great Wall: large slab of galaxies
• Coma Wall:
  • Great Wall: large slab of galaxies
• COMAP: high frequency radio telescope to map CO
  • Carbon Monoxide Mapping Array (COMA): planned experiment to observe epoch of reionization
• comatic aberration:
  • coma: aberration where points of light show a tail
• Combined Array for Research in Millimeter-wave Astronomy (CARMA): array of radio telescopes in eastern California
• combined differential photometric precision (CDPP): calculated relation of photometric variation to SNR
• Combined Radio All-sky Targeted Eight-GHz Survey:
  • CRATES: catalog of 8.4 GHz data on radio sources
• ComCam:
  • Giant Magellan Telescope (GMT): 24.5 meter telescope under construction
• comet: Sun-orbiting object with coma and possible tail
  • 67P/Churyumov-Gerasimenko (67P,67P/C-G): comet visited by Rosetta space mission
• Comet Astrobiology Exploration Sample Return:
  • CAESAR: planned space mission to return a sample of a comet
• Comet Galaxy: spiral galaxy in cluster Abell 2667
• Comet Giacobini-Zinner:
  • International Cometary Explorer (ICE): 1980s space mission flying by comets
• Comet Halley:
  • comet: Sun-orbiting object with coma and possible tail
  • Giotto: 1980s space mission carrying out a Comet Halley flyby
  • International Cometary Explorer (ICE): 1980s space mission flying by comets
  • long-period comet: comet with an orbital period of more than 200 years
  • Pioneer Venus Orbiter (PVO): NASA Venus probe launched 1978
  • SPARTAN: series of astronomy satellites launched/retrieved by space shuttle
• Comet P/Shoemaker-Levy:
  • comet: Sun-orbiting object with coma and possible tail
• comet planet: planet with some characteristics of a comet
• cometary globule:
  • Bok globule: dense molecular cloud
• cometary hydrogen cloud:
  • comet: Sun-orbiting object with coma and possible tail
• cometary nebula:
  • cloud: higher-density region of space
  • Parsamian Nebula Catalog: 1965 list of nebulae
  • reflection nebula: nebula made visible by light it scatters from nearby stars
• comets:
  • asteroid: minor planet without comet characteristics
  • CAESAR: planned space mission to return a sample of a comet
  • Catalogue of Cometary Orbits (CCO): comet catalog updated since 1970s
  • centaur: asteroid-like body orbiting among the outer planets
  • Hills cloud: cloud of comets and minor planets around the solar system
  • International Cometary Explorer (ICE): 1980s space mission flying by comets
  • Kuiper Belt (K Belt,KB): further part of solar system beyond Neptune
  • long-period comet: comet with an orbital period of more than 200 years
  • Oort Cloud: cloud of comets and minor planets around the solar system
  • Rosetta: space probe that visited a comet
  • Stardust: space mission that collected and returned comet coma dust
  • striae: parallel ridges
  • Uppsala-ESO Survey of Asteroids and Comets (UESAC): 1990s comet and asteroid survey
• COMICS:
  • Subaru Telescope: 8.2 meter telescope in Hawaii
• commensal mode: telescope usage that accomplishes multiple observations simultaneously
• commensurability:
  • orbital resonance: tendency of orbits of multiple bodies to remain in a simple pattern
• Commissariat à l'énergie atomique et aux énergies alternatives:
  • CEA Service d'Astrophysique (CEA SAp): French national astrophysics research institute
• Common Astronomy Software Application:
  • CASA: software package for radio interferometry image generation
• common envelope: binary star system surrounded by a single gas cloud
  • post-common envelope binary (PCEB): binary star system showing unusual stellar evolution
• common envelope binary:
  • common envelope: binary star system surrounded by a single gas cloud
  • post-common envelope binary (PCEB): binary star system showing unusual stellar evolution
• common envelope binary event:
  • common envelope: binary star system surrounded by a single gas cloud
  • post-common envelope binary (PCEB): binary star system showing unusual stellar evolution
• common proper motion:
  • proper motion (PM): apparent motion in relation to the position of the Sun
• Commonwealth Scientific and Industrial Research Organisation:
  • Australia Telescope Compact Array (ATCA): radio telescope in eastern Australia
• comoving coordinates:
  • comoving units: units of measure that incorporate the scale factor
• comoving density of star formation:
  • star formation rate (SFR): rate at which material such as gas is turned into stars
• comoving distance:
  • comoving units: units of measure that incorporate the scale factor
• comoving horizon:
  • particle horizon: furthest point from which light can reach us
• comoving SFR density:
  • star formation rate (SFR): rate at which material such as gas is turned into stars
• comoving SFRD:
  • star formation rate (SFR): rate at which material such as gas is turned into stars
• comoving space density:
  • comoving units: units of measure that incorporate the scale factor
• comoving speed:
  • comoving units: units of measure that incorporate the scale factor
• comoving star formation rate density:
  • star formation rate (SFR): rate at which material such as gas is turned into stars
• comoving units: units of measure that incorporate the scale factor
• comoving volume:
  • comoving units: units of measure that incorporate the scale factor
• CoMP:
  • High Altitude Observatory (HAO): NCAR unit observing and monitoring the Sun
• compact binary:
  • binary star: system of two stars co-orbiting
• compact galaxy:
  • dwarf galaxy: small galaxy with a few billion stars
• compact group:
  • galaxy group: group of fifty or fewer gravitationally bound Milky-Way-sized galaxies
• compact HII region:
  • HII region (HII): cloud of partially-ionized atomic hydrogen
• compact object (CO): dense astronomical body such as white dwarf or denser
• compact object binary:
  • galactic binary: system of two object co-orbiting within the Milky Way
• compact object merger:
  • compact object (CO): dense astronomical body such as white dwarf or denser
• Compact Object Mergers: Population Astrophysics and Statistics:
  • COMPAS: SPS code for compact object binaries
• compact objects:
  • COMPAS: SPS code for compact object binaries
  • galactic binary: system of two object co-orbiting within the Milky Way
• Compact Objects with ASKAP: Surveys and Timing:
  • Australian Square Kilometre Array Pathfinder (ASKAP): radio telescope array of 36 12-meter dishes
• compact star:
  • compact object (CO): dense astronomical body such as white dwarf or denser
• compact stellar nucleus:
  • stellar nucleus: group of many stars at the center of a galaxy
• COMPAS: SPS code for compact object binaries
• COMPLETE Survey: survey of star forming regions
• completeness: measure of how many of a survey's objects of a certain magnitude have been detected
• completeness limit:
  • completeness: measure of how many of a survey's objects of a certain magnitude have been detected
• complex:
  • molecular cloud: interstellar gas cloud that includes molecules
• complex crater: crater with central high-point
• complex numbers:
  • Euler's formula: formula relating exponentials to trigonometric functions
• Complex Visibility:
  • visibility: mathematical representation of interferometer's view
• composite boson:
  • particle: very small thing
• composite remnant:
  • supernova remnant (SNR): nebula of debris resulting from a supernova
• compound:
  • acetylene (C₂H₂): compound of two carbon and two hydrogen atoms
  • amine: type of compound containing nitrogen
  • ammonia (NH₃): particular compound of nitrogen and hydrogen
  • carbon dioxide (CO₂): compound of carbon atom and two oxygen atoms
  • carbon monoxide (CO): compound of carbon and oxygen, one atom each
  • ethylene (C₂H₄): compound of two carbon and four hydrogen atoms
  • glycine (Gly,G): smallest of the twenty common amino acids
  • hydrocarbon (HC): any compound of just carbon and hydrogen
  • hydrogen deuteride (HD): hydrogen molecule with one deuterium atom
  • hydroxyl (OH): neutral compound of hydrogen and oxygen, one atom each
  • methane (CH₄): compound of one carbon and 4 hydrogen atoms
  • methylidyne (CH): compound of one carbon and one hydrogen atom
  • nitrite (NO₂^-): ion of a nitrogen atom and two oxygen atoms with extra electron
  • polycyclic aromatic hydrocarbon (PAH): hydrocarbons consisting of meshes of benzene rings
  • silicate: type of compound including silicon and oxygen
• compound lens:
  • chromatic aberration: focusing different wavelengths differently
  • spherical aberration: mis-focusing by spherically-curved mirrors and lenses
• COMPTEL:
  • Compton Gamma Ray Observatory (CGRO,GRO): 1990s space observatory for gamma ray observation
• Compton camera:
  • Compton telescope: type of gamma ray telescope for 0.75-30 MeV range
• Compton cooling:
  • Compton scattering: photon collision with a charged particle that emits a different photon
• Compton effect:
  • Compton scattering: photon collision with a charged particle that emits a different photon
• Compton Gamma Ray Observatory (CGRO,GRO): 1990s space observatory for gamma ray observation
• Compton optical depth:
  • Thomson optical depth (τ_T,τ): a measure of effects of Thomson scattering
• Compton parameter:
  • Compton scattering: photon collision with a charged particle that emits a different photon
• Compton reflection: recognizable emission due to a gas or plasma's Compton scattering
• Compton scattering: photon collision with a charged particle that emits a different photon
  • Compton reflection: recognizable emission due to a gas or plasma's Compton scattering
  • Compton telescope: type of gamma ray telescope for 0.75-30 MeV range
  • electron scattering: any process that changes the course of an electron
  • Klein-Nishina formula: formula for the effects of electrons scattering photons
  • non-thermal emission: EMR not due to a body's heat
  • scintillator: instrument part designed to respond to high-energy photons
  • synchrotron self-Compton (SSC): charged particle cloud scattering its own synchrotron-produced photons
• Compton telescope: type of gamma ray telescope for 0.75-30 MeV range
• Compton thick:
  • Thomson optical depth (τ_T,τ): a measure of effects of Thomson scattering
• Compton upscattering:
  • Compton scattering: photon collision with a charged particle that emits a different photon
• Compton wavelength: lower bound on a particle's possible de Broglie wavelength
• Compton Y-parameter:
  • Compton scattering: photon collision with a charged particle that emits a different photon
• Comptonization:
  • Compton scattering: photon collision with a charged particle that emits a different photon
• computation:
  • adaptive mesh refinement (AMR): numerical modeling method balancing detail with tractability
  • basis function: one of a set of functions used to approximate a function of interest
  • Bernstein polynomial: polynomial form capable of producing arbitrary shapes
  • CIG: initiative to produce Earth-science software
  • cosmological simulation: simulation of the history of the universe
  • discontinuous Galerkin method: computational method for PDEs handling discontinuities
  • fast Fourier transform (FFT): efficient algorithm for calculating a discrete Fourier transform
  • finite difference method (FDM): means of estimating calculus and differential equation solutions
  • finite element method (FEM,FEA): computational method for PDEs suited to physical problems
  • finite volume method (FVM): computational method to PDEs especially suited to fluid dynamics
  • flux reconstruction (FR): numerical approach emphasizing joining the subdivisions
  • Godunov scheme: computational fluid dynamics method
  • high resolution shock capture (HRSC): method of modeling shock waves
  • Hough transform (HT): algorithm used in image processing
  • Krylov subspace method: efficient method of numerically solving sets of linear equations
  • lattice Boltzmann method (LBM): computational fluid dynamics method treating the fluid as particles
  • Markov chain Monte Carlo (MCMC): model technique to approximate multi-dimensional integrals
  • mass shell: conceptual volume of mass shaped like a hollow sphere
  • Message Passing Interface (MPI): mechanism for passing data between processors of a multiprocessor
  • numerical analysis: using equations through repetitive arithmetic
  • numerical relativity (NR): solving GR-sensitive problems with numerical methods
  • pipeline: set series of tasks to perform on something
  • quantum Monte Carlo (QMC): MC approach to difficult quantum mechanical problems
  • random forest: algorithmic method of developing decision trees
  • random walk: movement with random turns
  • Riemann problem: consequence of discontinuities in numerical methods
  • shearing box: method of simulating 3D MHD in disks
  • smoothed-particle hydrodynamics (SPH): computational method for simulating fluid flows
  • spectral method: method of numerically solving differential equations
  • stencil: pattern of input to numerical solutions at a point
  • task-based parallelism (TBP): breaking a computation into tasks that can be run in parallel
• computational astrophysics: astrophysical study through computer modeling
  • HARM²: technique for parallelizing computations of radiation with hydrodynamics
• computational fluid dynamics:
  • lattice Boltzmann method (LBM): computational fluid dynamics method treating the fluid as particles
• Computational Infrastructure for Geodynamics:
  • CIG: initiative to produce Earth-science software
• computational physics:
  • computational astrophysics: astrophysical study through computer modeling
• computerized tomography scan:
  • tomography: observation of sections of a 3D object
• computing:
  • data cube: "table" of numerical data covering three dimensions
  • exascale computing: exaFLOP computing capability, i.e., quintillion FLOPs
• concept:
  • AtLAST: plan for submillimeter telescope in Chile
  • California Extremely Large Telescope (CELT): concept for an extremely large telescope
  • Europa Lander: plan for a mid 2020s Europa probe landing on the surface
  • Giant Segmented Mirror Telescope (GSMT): concept for an extremely large telescope
  • STAR-X: concept for a future X-ray space telescope
  • starshade: spacecraft to block light from a specific body
• Concept 1:
  • Origins Space Telescope (OST): concept for future very large space IR telescope
• Concept 2:
  • Origins Space Telescope (OST): concept for future very large space IR telescope
• CONCERTO: spectrometer aimed at mapping the [CII] line
• concordance model:
  • alternative cosmologies: cosmological models other than Big Bang/Lambda-CDM
• condensation:
  • refractory material: material with high condensation temperature
  • volatile material: material with low condensation temperature
• condensation temperature:
  • refractory material: material with high condensation temperature
  • volatile material: material with low condensation temperature
• conditional luminosity function (CLF): function characterizing luminosity of galaxies with a given halo mass
• conditional mass function:
  • conditional stellar mass function (CSMF): function characterizing galaxies within a halo of a given mass
• conditional stellar mass function (CSMF): function characterizing galaxies within a halo of a given mass
• conductance:
  • siemens (S): SI unit of electrical conductance
• conduction:
  • stellar structure: the presumed internal structure of stars
  • white dwarf (WD): stellar remnant of mostly electron degenerate matter
• conductive hydrogen:
  • metal: in astrophysics, any element more massive than helium
  • metallic hydrogen: a high-pressure state of hydrogen that is conductive
• conductivity:
  • siemens (S): SI unit of electrical conductance
• confidence interval:
  • error bar: feature of a graph to indicate accuracy
• configuration:
  • monolithic mirror: telescope mirror made of one piece of material
  • segmented mirror: a telescope mirror formed of array of smaller mirrors
• conformal field theory (CFT): a type of quantum field theory
  • anti-de Sitter space (AdS): type of curved space
• conformal mapping:
  • conformal field theory (CFT): a type of quantum field theory
• conformal transformation:
  • conformal field theory (CFT): a type of quantum field theory
• confusion:
  • confusion limit: limit on telescope imaging due to too many sources in the same region
• confusion limit: limit on telescope imaging due to too many sources in the same region
• confusion-limited image:
  • confusion limit: limit on telescope imaging due to too many sources in the same region
• conic section: orbit shapes, like the intersection of a plane and cone
• conjunction:
  • celestial event: generally something happening visible in the sky
  • heliocentric system: model of the universe with the planets orbiting the Sun
• CONSERT:
  • Rosetta: space probe that visited a comet
• conservation law: property that remains unchanged by physical phenomena
• consortium:
  • Astronet: European astronomy consortium
  • European Pulsar Timing Array (EPTA): European collaboration of radio telescopes
  • International Pulsar Timing Array (IPTA): organization of pulsar timing arrays
  • MicroFUN (μFUN): observers following up on microlensing events in the galactic bulge
  • NANOGrav: effort to detect gravitational waves through pulsar timing
  • pulsar timing array (PTA): cooperating set of pulsar timing observatories
  • SuperWASP (SWASP): broad Earth-based search for transiting planets
  • WASP: multi-university initiative to locate transiting planets
• constant:
  • Avogadro's number (N_A): roughly number of hydrogen atoms in a gram
  • Boltzmann constant (k,k_B): relates particle energy and temperature
  • Chandrasekhar limit: maximum mass of a white dwarf
  • gravitational constant (G): indicates how much pull between two masses
  • GZK limit: limit on energy of cosmic rays
  • Hubble constant (H₀): current rate of expansion of the universe
  • Hubble time (t_H): approximation of the age of the universe
  • Oort constants: two constants characterizing local Milky-Way motion
  • Planck constant (h): quantum of action in quantum mechanics
  • Schönberg-Chandrasekhar limit: maximum stellar isothermal helium core mass
  • solar constant: flux from the Sun at 1 AU
  • Stefan-Boltzmann constant (σ): relates radiation power to temperature and surface area
  • Tolman-Oppenheimer-Volkoff limit (TOV,LOV): maximum mass of a neutron star
• constellation: division of the celestial sphere
  • asterism: easily recognizable star pattern
  • Orion: well-known constellation in the northern hemisphere
• constitutive equations:
  • equation of state (EoS): equation relating temperature, pressure, and volume
• constitutive relations:
  • equation of state (EoS): equation relating temperature, pressure, and volume
• construction:
  • 4MOST: spectrograph in development for VISTA telescope
  • BlackGEM: telescope array in development to follow up gravitational wave signals
  • Cherenkov Telescope Array (CTA): ground gamma-ray telescope array in development
  • Dark Energy Spectroscopic Instrument (DESI): new instrument for measuring red-shift of distant objects
  • Euclid: planned observatory-satellite to measure dark energy
  • European Extremely Large Telescope (E-ELT,ELT): 39-meter telescope under construction
  • FAST: Arecibo-like 500 m telescope in deployment in China
  • Giant Magellan Telescope (GMT): 24.5 meter telescope under construction
  • HIRAX: radio telescope array 21-cm surveying
  • James Webb Space Telescope (JWST): future space-based 6.5 meter infrared telescope
  • JUICE: mission to Jupiter in development
  • Keck Planet Finder (KPF): spectrograph in development for Keck
  • Keck Planet Imager and Characterizer (KPIC): extreme AO upgrade under development for Keck
  • Multi-object Optical and Near-IR Spectrograph (MOONS): advanced spectrograph under development for VLT
  • NIRPS: near-infrared extension to HARPS spectrograph
  • Northern Extended Millimeter Array (NOEMA): large radio telescope array under construction in Europe
  • OSAM-1: prototype space robot for servicing satellites
  • PLATO: planned observatory-satellite aimed at finding exoplanets
  • QUBIC: survey to measure the polarization of the CMB
  • Rosalind Franklin: Mars rover in development for 2020 launch
  • Rubin Observatory (VRO,LSST): 8-meter survey reflector telescope under construction in Chile
  • Solar Orbiter (SolO): Sun-observing satellite in development
  • Thirty Meter Telescope (TMT): extremely large telescope planned for Hawaii
  • TolTEC: sensitive infrared camera under construction for the LMT
  • University of Tokyo Atacama Observatory (TAO): observatory for a 6.5 m infrared telescope under construction
  • WEAVE: spectrograph under construction for the William Herschel Telescope
• constructive interference:
  • interference: result of interaction of waves
• contact binary: binary stars orbiting so close they are touching
  • binary star: system of two stars co-orbiting
  • black hole merger: two black holes meeting and forming one
• contamination:
  • completeness: measure of how many of a survey's objects of a certain magnitude have been detected
• continuous absorption: the absorption of a whole section of a spectrum
• continuous Galerkin method:
  • discontinuous Galerkin method: computational method for PDEs handling discontinuities
• continuous random variable:
  • probability density function (PDF): shows probability of taking a particular value from a continuous range
  • probability mass function (PMF): shows probability of taking one of a number of discrete values
• continuous shock:
  • shock wave: abrupt propagating disturbance in a fluid
• continuous spectrum: smooth spectrum or portion of spectrum with no lines
• continuous viewing zone (CVZ): region of sky that can be viewed 7×24×365
• continuous-wave frequency-modulated:
  • frequency modulation (FM): changing the frequency of a signal's carrier
• continuum: portion of a continuous spectrum not affected by a spectral feature
  • continuous absorption: the absorption of a whole section of a spectrum
  • continuous spectrum: smooth spectrum or portion of spectrum with no lines
  • continuum emission: continuous spectrum such as black body radiation or bremsstrahlung
• continuum emission: continuous spectrum such as black body radiation or bremsstrahlung
• convection:
  • convection zone: region of a star transmitting energy through convection
  • mixing length theory: tractable simplified model of convection
  • Rayleigh number (Ra): measure reflecting a fluid system's propensity to turbulence
  • RT instability: result of lighter fluid pushing a heavier fluid
  • stellar structure: the presumed internal structure of stars
• convection zone: region of a star transmitting energy through convection
• convective mantle:
  • dynamo: mechanism for generating magnetic fields around astronomical bodies
• convective parameterization:
  • subgrid-scale physics: shortcuts handling physics on a smaller scale than a simulation's grid
• convective region:
  • convection zone: region of a star transmitting energy through convection
• convective Rossby number:
  • Rossby number (Ro): ratio of inertial to Coriolis force
• convective Urca process:
  • Urca process: neutrino-emitting process
• convective zone:
  • convection zone: region of a star transmitting energy through convection
• convergent point:
  • moving-cluster method: method of measuring distance to a nearby star cluster
• convergent point method:
  • moving-cluster method: method of measuring distance to a nearby star cluster
• convolution: type of product function of two functions
• convolutional neural network (CNN): type of image processing software
  • U-Net: neural network software for image reconstruction
• COO:
  • double star designation: systems and format of double star designators
• cool carbon star:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• cool galactic carbon star:
  • carbon star (C): star with more carbon than oxygen in its atmosphere
• cooling flow: inward flow of ICM within galaxy clusters
  • Zwicky 3146 (Zw 3146,ZwCl 1021.0+0426): nearby large galaxy cluster
• cooling flow problem:
  • cooling flow: inward flow of ICM within galaxy clusters
• cooling function: function relating a gas's cooling rate to its temperature
• cooling timescale:
  • giant planet: planet of more than 10 Earth masses
  • timescale (t,τ): general length of time something takes
• Cooper pair: pair of electrons sharing a particular type of bond
• coordinate:
  • declination (dec): direction coordinate above/below celestial equator
  • epoch: when an object was at a particular set of celestial coordinates
  • meridian: circle around the Earth passing through both poles
  • right ascension (RA): direction coordinate along celestial equator
  • terrestrial time (TT): current measure of time for astronomical observations on Earth
• coordinate distance:
  • comoving units: units of measure that incorporate the scale factor
• coordinate system:
  • ecliptic coordinate system: celestial coordinate system system based upon Earth's orbital plane
  • equatorial coordinate system: latitude/longitude-like system for the celestial sphere
  • galactic coordinate system (GCS): celestial coordinate system system based upon the galactic plane
  • horizontal coordinate system: celestial coordinate system based upon horizon and north
  • International Celestial Reference System (ICRS): standardized variation of equatorial coordinate system
  • supergalactic coordinate system: celestial coordinate system system based upon the supergalactic plane
• Coordinated Molecular Probe Line Extinction Thermal Emission Survey:
  • COMPLETE Survey: survey of star forming regions
• coordinated universal time:
  • time standard: method of designating points in time and quantifying time periods
• coordinates:
  • celestial coordinate system: system for specifying position of celestial objects
  • celestial equator: equator-like line around the celestial sphere
  • celestial pole: point within the celestial sphere aligned with Earth's rotation axis
  • celestial sphere: the sky in considered as a sphere surrounding the observer
  • ecliptic: path of the Sun on the celestial sphere as seen from Earth
  • equinox: times when tilt of Earth is neither toward or away from the Sun
  • galactic north: determination of the more northern direction of the Milky Way's axis
  • galactic plane: plane in which the stars of the Milky Way reside
  • phone number: colloquial expression for coordinates
  • plane of the sky (POS): plane tangent to the celestial sphere
  • solar time: time based upon the position of the Sun in the Earth's sky
  • torus coordinates: coordinates for toruses
• Coordinates, Sizes, Magnitudes, Orientation, and Shapes:
  • SuperCOSMOS Sky Survey (SSS): survey of stars and galaxies from legacy plates
• Copernicus:
  • Orbiting Astronomical Observatory (OAO): series of 1960s-1970s NASA space telescopes
• coplanar flip:
  • planetary migration: change in planet's orbit
• COPSS: survey of CO from star forming epoch
• Cordelia:
  • shepherd moon: small moon at outer edge of a ring
• Cordoba Durchmusterung:
  • Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
• core:
  • carbonate-silicate cycle: long-term cycle that sequesters Earth carbon
  • core-cusp problem: theories and observation show different dwarf galaxy rotation curves
  • dense core: dense molecular cloud
  • gas planet: planet made largely of gas
  • stellar core: the middle of a star
• core accretion:
  • core accretion model: model for the formation of giant planets
• core accretion model: model for the formation of giant planets
  • giant planet formation: process by which giant planets form
• core barrier:
  • planet formation: process by which planets form
• core collapse: results when the center of something loses its pressure
  • globular cluster (GC): spherical group of stars orbiting a galaxy
  • Messier 15 (M15): globular cluster with collapsed core
• core collapse progenitor:
  • core collapse supernova (CCSN): supernova resulting from the collapse of the core of a star
• core collapse supernova (CCSN): supernova resulting from the collapse of the core of a star
  • core collapse: results when the center of something loses its pressure
  • supernova (SN): stellar explosion larger than a nova
  • supernova progenitor: the star or star system that produces a supernova
• core collapse supernova progenitor:
  • supernova progenitor: the star or star system that produces a supernova
• core flash:
  • helium flash: helium ignition in a star
• core mass function:
  • dense core mass function (DCMF,CMF): function describing range of masses of dense cores
• core-cusp problem: theories and observation show different dwarf galaxy rotation curves
• core-driven escape:
  • atmospheric escape: escape of gas particles from a planet's atmosphere
• core-mantle boundary:
  • cosmic microwave background (CMB,CMBR,CBR,MBR): microwave radiation coming from every direction
• Coriolis effect:
  • Coriolis force: apparent force in a rotating frame of reference
  • Hadley cell: circulation pattern of up at the equator, poleward, down, and back
• Coriolis force: apparent force in a rotating frame of reference
• CorMASS: near-infrared spectrograph
• Cornell Caltech Atacama Telescope:
  • CCAT: 25-meter submillimeter telescope plan for Chile
• Cornell Massachusetts Slit Spectrograph:
  • CorMASS: near-infrared spectrograph
• Cornell University:
  • Carl Sagan Institute (CSI): group researching finding life on other planets and moons
• corona: plasma surrounding a star
  • coronagraph: telescope feature to block light from a specific body
  • coronal hole: cool, low-density portions of the Sun's corona
  • coronal mass ejection (CME): mass of plasma ejected from the Sun
  • Coronal Solar Magnetism Observatory (COSMO): proposed solar observatory
  • flux rope: rope-shaped structure in magnetic fields associated with coronal mass ejections
  • magnetic arcade: series of arch-like magnetic flux lines on the Sun
  • solar flare: sudden brightening of the Sun
  • solar wind: charged particles emanating from the Sun
  • standard model of a flare: description of how solar flares function
  • stellar atmosphere: photosphere and above
  • Sun surface features: features on the Sun's surface
  • TRACE: former solar observing satellite
  • transition region: middle layer of the Sun's atmosphere
• coronagraph: telescope feature to block light from a specific body
  • corona: plasma surrounding a star
  • solar telescope: telescope designed to observe the Sun
• coronagraphy:
  • coronagraph: telescope feature to block light from a specific body
• coronal gas:
  • interstellar medium (ISM): matter within a galaxy between star systems
• coronal hole: cool, low-density portions of the Sun's corona
  • Sun surface features: features on the Sun's surface
• coronal loop:
  • magnetic arcade: series of arch-like magnetic flux lines on the Sun
• coronal mass ejection (CME): mass of plasma ejected from the Sun
  • ejection: forcing or throwing something out
  • Forbush decrease: decrease in cosmic rays after a coronal mass ejection
  • mass: object's quality that determines the effects of forces and gravity
  • solar flare: sudden brightening of the Sun
  • solar particle event (SPE): episode of higher velocity solar wind
  • space weather: varying conditions in space affecting Earth and humans
  • Sun surface features: features on the Sun's surface
• Coronal Solar Magnetism Observatory (COSMO): proposed solar observatory
• COROT: observatory-satellite to look for transiting exoplanets and stellar oscillations
• corotation resonance (CR): an orbital resonance with the same frequency as the orbit
• corotation torque: torque on a planet from coorbiting planetary disk material
• corrected AIC:
  • Akaike information criterion (AIC): particular formula for comparison of statistical models
• correction:
  • gravity anomaly: difference between measured gravity and that predicted by a model
• Corrective Optics Space Telescope Axial Replacement:
  • Hubble Space Telescope (HST): observatory-satellite with 2.4 meter reflective telescope
• correlation function:
  • N-point function: general term for analyses-techniques of spatial data
• correlator: unit that interferes wave signals for interferometry
• CORSA-b:
  • Japan Aerospace Exploration Agency (JAXA): Japan agency includes astronomical research
• Corvus:
  • Sloan Great Wall (SGW): large slab of galaxies discovered in SDSS
• COS:
  • Hubble Space Telescope (HST): observatory-satellite with 2.4 meter reflective telescope
• COSAC:
  • Rosetta: space probe that visited a comet
• COSI: 2000s balloon-based gamma ray telescope
• COSIMA:
  • Rosetta: space probe that visited a comet
• COSMIC:
  • Hale Telescope: 5.1 m reflector telescope in California
• Cosmic Anisotropy Polarization Mapper:
  • CAPMAP: early 2000s array that surveyed CMB polarization
• Cosmic Anisotropy Telescope (CAT): 1990s interferometer to measure CMB variations
• Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS): early universe survey by HST
• Cosmic Background Explorer (COBE): 1989 satellite for observing the CMB
• Cosmic Background Imager (CBI): radio telescope in Chile observing the CMB
• cosmic background radiation (CBR): electromagnetic radiation coming from every direction
• cosmic censorship hypothesis:
  • law of cosmic censorship: a singularity cannot be observed
• cosmic distance:
  • standard candle: astronomical object whose brightness can be determined
  • standard ruler: astronomical phenomenon whose size can be determined
• cosmic distance ladder: sequence of methods of measuring distance to astronomical objects
  • standard siren: transient whose gravitational waves indicate a specific distance
• cosmic distance scale:
  • cosmic distance ladder: sequence of methods of measuring distance to astronomical objects
  • standard candle: astronomical object whose brightness can be determined
  • standard ruler: astronomical phenomenon whose size can be determined
• cosmic dust: cosmic dust is dust in space such as interstellar dust
• Cosmic Dust Analyzer:
  • Cassini: explorer spacecraft sent to Saturn
• Cosmic Evolution Survey (COSMOS): investigation of dark matter and the universe's large scale structure
• Cosmic Explorer: concept for a very large LIGO-like GW detector
• Cosmic Explorer 1:
  • Cosmic Explorer: concept for a very large LIGO-like GW detector
• Cosmic Explorer 2:
  • Cosmic Explorer: concept for a very large LIGO-like GW detector
• cosmic gamma ray background (CGB): gamma-ray radiation seen everywhere
• cosmic high noon:
  • peak star-formation epoch: around 10 billion years ago when star formation peaked
• Cosmic Hot Interstellar Plasma Spectrometer Satellite:
  • CHIPSat: small satellite to investigate ISM plasma
• cosmic inflation:
  • inflation: theorized rapid expansion of the very early universe
• cosmic infrared background (CIB,CIBR): widespread infrared radiation not associated with known sources
• cosmic lens:
  • current sheet: narrow sheet within a magnetic field where current flows
• Cosmic Lens All-sky Survey (CLASS): radio survey aimed at gravitational lenses
• cosmic light horizon:
  • particle horizon: furthest point from which light can reach us
• cosmic microwave background (CMB,CMBR,CBR,MBR): microwave radiation coming from every direction
  • initial fluctuations: early universe density variations leading to current universe
• cosmic microwave background dipole:
  • CMB anisotropies: variations in the spectrum of the CMB
• cosmic microwave background radiation:
  • cosmic microwave background (CMB,CMBR,CBR,MBR): microwave radiation coming from every direction
• cosmic neutrino background:
  • cosmic background radiation (CBR): electromagnetic radiation coming from every direction
• cosmic noon:
  • peak star-formation epoch: around 10 billion years ago when star formation peaked
• cosmic optical background (COB): widespread optical radiation not associated with known sources
• cosmic ray astronomy:
  • cosmic rays (CR): very-high-energy particles from beyond the solar system
• cosmic ray background:
  • cosmic rays (CR): very-high-energy particles from beyond the solar system
• cosmic ray spallation:
  • lithium (Li): metal, Li, atomic number 3
  • nucleosynthesis: creation of atomic nuclei
• cosmic rays (CR): very-high-energy particles from beyond the solar system
  • Advanced Composition Explorer (ACE): satellite collecting solar wind and cosmic rays
  • air shower: particles and EMR generated in the atmosphere incoming particle or EMR
  • ARGO-YBJ Experiment: cosmic-ray/gamma-ray detector in Tibet
  • EUSO-SPB: balloon-born cosmic ray observatory
  • Forbush decrease: decrease in cosmic rays after a coronal mass ejection
  • GZK limit: limit on energy of cosmic rays
  • INTEGRAL: European gamma ray observatory-satellite
  • LOPES: cosmic ray detector that detected resulting radio
  • Orbiting Wide-angle Light Collectors (OWL): planned space mission to detect cosmic rays through Earth atmosphere light flashes
  • PAMELA: cosmic ray detector attached to satellite
  • Pierre Auger Observatory (PAO): cosmic-ray observatory in Argentina
  • Tunka experiment: Russian Cherenkov detector aimed at cosmic rays and gamma rays
• cosmic ruler:
  • cosmic distance ladder: sequence of methods of measuring distance to astronomical objects
• cosmic string: rent in spacetime
  • topological defect: defect in space that could arise in the early universe
• cosmic time: time since the Big Bang
• cosmic time dilation:
  • cosmological time dilation: very distant events appear to take longer
• cosmic variance: density variation on a cosmic scale
• cosmic void:
  • void: empty spaces between large scale structures
• cosmic web: hypothesized structure of the dark matter throughout the universe
  • dark matter filament: hypothesized type of long, thin volume of dark matter
  • large scale structure (LSS): the universe's structure as in placement of clusters
• cosmic X-ray background (CXB,CXRB,CXBR): X-ray radiation coming from outside the Milky Way
• cosmic X-ray background radiation:
  • cosmic X-ray background (CXB,CXRB,CXBR): X-ray radiation coming from outside the Milky Way
• cosmic X-ray survey:
  • X-ray: electromagnetic radiation, wavelength 0.01 to 10 nanometers
• cosmic year:
  • Milky Way: our galaxy
• COSMO:
  • Coronal Solar Magnetism Observatory (COSMO): proposed solar observatory
• COSMO11:
  • COSMOSOMAS: microwave survey
• COSMO15:
  • COSMOSOMAS: microwave survey
• cosmogony:
  • cosmology: study of the life of the universe
• cosmological:
  • cosmology: study of the life of the universe
• cosmological band shifting:
  • band shifting: effect of redshift on photometry
• cosmological constant (Λ): force counteracting the universe's inward gravitational pull
• cosmological distance ladder:
  • cosmic distance ladder: sequence of methods of measuring distance to astronomical objects
• cosmological horizon:
  • particle horizon: furthest point from which light can reach us
• cosmological inflation:
  • inflation: theorized rapid expansion of the very early universe
• cosmological models:
  • Alcock-Paczyński effect 2 (AP effect): type of distortion of the apparent depth of galaxy clusters
• cosmological principle: on a large scale the universe is the same everywhere
• cosmological redshift:
  • redshift (z): change to longer wavelengths due to Doppler effects
• cosmological simulation: simulation of the history of the universe
  • computational astrophysics: astrophysical study through computer modeling
• cosmological simulations:
  • cosmic web: hypothesized structure of the dark matter throughout the universe
  • dark matter filament: hypothesized type of long, thin volume of dark matter
• Cosmological Structures On Medium Angular Scales:
  • COSMOSOMAS: microwave survey
• cosmological time dilation: very distant events appear to take longer
  • time dilation: relativity's ability to make time differ for different objects
• cosmological zoom simulation: cosmological simulation plus higher resolution simulations of selected space
• cosmology: study of the life of the universe
  • 21-cm experiment: search for redshifted 21-cm hydrogen emission lines
  • Alcock-Paczyński effect 2 (AP effect): type of distortion of the apparent depth of galaxy clusters
  • alternative cosmologies: cosmological models other than Big Bang/Lambda-CDM
  • angular power spectrum: method of characterizing the CMB
  • anisotropy: directional-dependence such as temperature variation around the CMB
  • baryon acoustic oscillations (BAO): density fluctuations stemming from acoustic waves in the early universe
  • Baryon Oscillation Spectroscopic Survey (BOSS): survey of spatial distribution of luminous red galaxies and quasars
  • BICEP2: survey to measure the polarization of the CMB
  • Big Bang: theoretical event when the universe expanded from a point
  • Big Bang nucleosynthesis (BBN): creation of atomic nuclei in the very early universe
  • BigBOSS: BOSS survey follow-on
  • Bolshoi simulation: cosmological simulation
  • BOOMERanG: 1990s-2000s balloon-borne 1.3-meter millimeter telescope
  • brane: mathematical object with dimensions
  • Butcher-Oemler effect (BOE): observation of more blue galaxies at z > 0.3
  • Calán/Tololo Survey: late 1980s to early 1990s search to redshift 0.1
  • Carnegie Supernova Project (CSP): survey of supernovae lightcurves
  • chemical equilibrium (CE): state where chemical makeup is unchanging
  • CMB anisotropies: variations in the spectrum of the CMB
  • CMB polarization: effects of scattering and lensing on the CMB
  • CMBFAST: software to calculate CMB anisotropies
  • cold dark matter (CDM): one of three types of "dark matter" theory
  • comoving units: units of measure that incorporate the scale factor
  • core-cusp problem: theories and observation show different dwarf galaxy rotation curves
  • Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS): early universe survey by HST
  • Cosmic Evolution Survey (COSMOS): investigation of dark matter and the universe's large scale structure
  • cosmic time: time since the Big Bang
  • cosmic variance: density variation on a cosmic scale
  • cosmological constant (Λ): force counteracting the universe's inward gravitational pull
  • cosmological principle: on a large scale the universe is the same everywhere
  • cosmological simulation: simulation of the history of the universe
  • cosmological time dilation: very distant events appear to take longer
  • cosmological zoom simulation: cosmological simulation plus higher resolution simulations of selected space
  • critical density (ρ_c): density of the universe which leaves it flat
  • curvature: unflatness of space
  • D56: a target survey field of ACT telescope
  • dark age: interval when the universe's hydrogen atoms were neutral
  • dark energy: energy theorized to accelerate the expansion of the universe
  • Dark Energy Spectroscopic Instrument (DESI): new instrument for measuring red-shift of distant objects
  • dark flow: non-random patterns in peculiar velocity of galaxy clusters
  • decoupling: some type of particle stops being destroyed as often as it is created
  • Deep Lens Survey (DLS): investigating mass distribution of the universe
  • diffusion damping: a damping process within the plasma during recombination
  • dwarf galaxy problem: theories have more dwarf galaxies than are observed
  • EAGLE: simulation of galaxy formation and evolution
  • early universe: from the Big Bang to recombination
  • EBEX: balloon-based CMB polarization survey
  • Einstein-de Sitter model: universe tuned to the smallest expansion that continues forever
  • Enzo: hydrodynamic simulation system
  • epoch of reionization (EOR): time when the universe's neutral hydrogen atoms ionized
  • escape fraction: fraction of ionizing photons escaping a body
  • ESSENCE: survey using supernova data to study dark energy
  • false vacuum: apparent QM vacuum
  • FIRE Simulations: high resolution simulation of galaxies
  • foreground subtraction: removing unwanted sources of EMR in intensity mapping
  • freeze-out: particles existing long-term after a decoupling
  • Friedmann model: type of model of universe incorporating general relativity
  • fuzzy dark matter (FDM): concept of extremely light dark matter particles
  • GADGET-2: an n-body/SPH simulation computer program
  • galaxy bias: degree to which galaxy density fails to correspond to dark matter density
  • galaxy filament: thread-like formations of galaxies, 50 to 80 megaparsecs
  • galaxy power spectrum: a power spectrum describing the occurrence of galaxies in space
  • Gunn-Peterson trough: spectral feature in EMR from redshift 6+
  • halo mass function: mass of distribution of dark matter
  • hierarchical assembly of galaxies: development of large galaxies by combining small ones
  • Hubble constant (H₀): current rate of expansion of the universe
  • Hubble diagram: diagram comparing redshift with distance
  • Hubble expansion: ongoing expansion of the universe
  • inflation: theorized rapid expansion of the very early universe
  • initial fluctuation spectrum: the power spectral density of the early universe
  • initial fluctuations: early universe density variations leading to current universe
  • intensity mapping: measure of cosmic matter density
  • intergalactic dust: dust not within galaxies
  • isotropy: uniformity in all directions
  • Kapteyn universe: early 20th century model of the universe centered on the Milky Way
  • Lambda-CDM model (ΛCDM,LCDM): Big-Bang cosmological model with a cosmological constant and cold dark matter
  • large scale structure (LSS): the universe's structure as in placement of clusters
  • LasDamas: simulations of large scale evolution of dark matter and galaxies
  • Lick Observatory Supernova Search (LOSS): search for supernovae for cosmological study
  • LiteBIRD: planned spacecraft to map CMB polarization
  • LSPE-SWIPE: plan for a balloon-based CMB polarization survey
  • luminosity distance (d_L, D_L): distance to an object based upon the distance's effect on received flux
  • Multi-Epoch Nearby Cluster Survey (MENeaCS): Type Ia supernova survey in clusters at z = 0.1
  • N-point function: general term for analyses-techniques of spatial data
  • NOAO Deep Wide-field Survey (NDWFS): survey investigating large scale structure of the universe
  • observable universe: that part of the universe that we can conceivably observe
  • Olbers' paradox: argument using the dark of the sky regarding the nature of the universe
  • Pantheon: catalog of well-checked Type Ia supernovae
  • particle horizon: furthest point from which light can reach us
  • peak star-formation epoch: around 10 billion years ago when star formation peaked
  • pion (π): first type of meson discovered
  • primordial black hole: black holes forming at the most dense volumes when inflation ceased
  • primordial gravitational waves: gravitational waves formed in the early universe
  • PROMETHEUS/VERTEX: hydrodynamic simulation system
  • protogalaxy: gas cloud forming a galaxy
  • QUaD: survey to measure the polarization of the CMB
  • quark-gluon plasma (QGP): extreme-temperature state of matter
  • QUBIC: survey to measure the polarization of the CMB
  • QUIET: survey to measure the polarization of the CMB
  • radiation era: early universe era when radiation pressure dominated
  • radio source counts: using radio source population characteristics to determine curvature
  • RAMSES: hydrodynamic simulation system
  • Randall-Sundrum model (RS model): particular 5-dimensional cosmological model
  • recombination: time when the universe's ionized hydrogen atoms neutralized
  • redshift survey: survey of the universe aiming at three dimensions
  • redshift-angular size relation: how observed size depends on redshift
  • redshift-magnitude relation: how apparent magnitude depends on redshift
  • reheating: theorized increase in temperature after cosmological inflation
  • relic: particles left over from the events of the early universe
  • repulsive dark matter (RDM): concept of dark matter that resists extreme dark-matter density
  • RHAPSODY: simulation of galaxy cluster dark-matter halos
  • Sachs-Wolfe effect (SWE,SWeffect): gravitational redshift of the CMB
  • satellite plane problem: satellite galaxies inexplicably tend to fall in a plane
  • scale factor (a): relative size of the universe as a function of time
  • Scott effect: bias toward finding clusters that have bright galaxies
  • spacetime diagram: graph of simplified spacetime, with fewer space dimensions
  • Sunyaev-Zel'dovich effect (SZ effect,SZ,SZE): type of distortion of the CMB
  • Supernova Cosmology Project (SCP): used supernova data to determine a history of the universe's expansion
  • Supernova Legacy Survey (SNLS): detect and monitor supernovae to measure the effects of dark energy
  • surface of last scattering: sphere around us from which CMB photons are just reaching us
  • symmetry breaking: loss of symmetry, such as due to loss of stability in a regime change
  • Tenerife Experiment: 1980s-1990s survey of CMB anisotropies
  • Theory of Everything (TOE): single law explaining the four forces of nature
  • tired light: theory that light becomes red for reasons other than Doppler shift
  • topological defect: defect in space that could arise in the early universe
  • VIMOS-VLT Deep Survey (VVDS): spectroscopic survey of 100,000 high-redshift galaxies
  • void: empty spaces between large scale structures
  • Wide-field Multi-object Spectrograph (WFMOS): proposed instrument to detect baryon acoustic oscillations
  • Wilkinson Microwave Anisotropy Probe (WMAP): spacecraft that measured variations in the cosmic background radiation
  • Zel'dovich approximation: model of the formation of cosmological structure
• Cosmology Large Angular Scale Surveyor:
  • Cosmic Lens All-sky Survey (CLASS): radio survey aimed at gravitational lenses
• cosmology simulation:
  • cosmological simulation: simulation of the history of the universe
• COSMOS:
  • Cosmic Evolution Survey (COSMOS): investigation of dark matter and the universe's large scale structure
  • cosmology: study of the life of the universe
  • DEVILS: visible-light spectrographic survey of 56k distant galaxies
  • FourStar Galaxy Evolution Survey (ZFOURGE,Z-FOURGE): infrared deep-survey to detect galaxies
  • MIGHTEE: radio survey of four established deep fields
  • SuperCOSMOS Sky Survey (SSS): survey of stars and galaxies from legacy plates
  • Víctor M. Blanco Telescope: 4 m reflector telescope in Chile
• COSMOS Field:
  • Cosmic Evolution Survey (COSMOS): investigation of dark matter and the universe's large scale structure
• COSMOSOMAS: microwave survey
• COSPIN:
  • Ulysses: space mission to observe the Sun from off the ecliptic
• COSTAR:
  • Hubble Space Telescope (HST): observatory-satellite with 2.4 meter reflective telescope
• COSTEP:
  • Solar and Heliospheric Observatory (SOHO): satellite observing the Sun
• COU:
  • double star designation: systems and format of double star designators
• coudé focus:
  • coudé focus telescope: type of Nasmyth telescope with additional mirrors
• coudé focus telescope: type of Nasmyth telescope with additional mirrors
• coulomb:
  • tesla (T): unit of magnetic flux density
• Coulomb force:
  • Coulomb's law: static electrical force relation
  • Vlasov-Poisson equation: equation describing plasma ignoring the magnetic field
• Coulomb scattering:
  • stellar encounter: stars passing close to each other
• Coulomb's constant:
  • Coulomb's law: static electrical force relation
• Coulomb's law: static electrical force relation
  • electric field (E): electric force as distributed over a space
• Council of Giants: twelve large galaxies surrounding the Local Group
• counterpart: image found at same coordinates using different EMR
• coupling constant:
  • quantum field theory (QFT): reworking of quantum mechanics incorporating fields
• Courant condition:
  • finite difference method (FDM): means of estimating calculus and differential equation solutions
• Courant-Friedrichs-Lewy-condition:
  • finite difference method (FDM): means of estimating calculus and differential equation solutions
• covalent bond:
  • adsorption: adhesion to a surface
  • oxidation state: number of electrons loaned out by an atom in an ionic bond
• CP:
  • Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
  • chemically peculiar star (CP star): star with SED showing presence metals unusual for stars
  • millisecond pulsar (MSP): pulsar spinning with a period in the range of milliseconds
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CP 1919:
  • pulsar (PSR): type of astronomical body with EMR in regular cycles of seconds or less
• CP star:
  • chemically peculiar star (CP star): star with SED showing presence metals unusual for stars
• CP symmetry:
  • axion (A⁰): proposed light, electrically neutral elementary particle
• CP1:
  • chemically peculiar star (CP star): star with SED showing presence metals unusual for stars
• CP2:
  • chemically peculiar star (CP star): star with SED showing presence metals unusual for stars
• CP3:
  • chemically peculiar star (CP star): star with SED showing presence metals unusual for stars
• CP4:
  • chemically peculiar star (CP star): star with SED showing presence metals unusual for stars
• CPC:
  • IRAS: 1983 satellite that surveyed the sky in infrared
• CPD:
  • Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
• CPO:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CPR:
  • circular polarization ratio (CPR): ratio of circular polarization handedness in reflected radar signal
• CR:
  • Collinder Catalog (Cr): 1930s catalog of 471 open clusters
  • corotation resonance (CR): an orbital resonance with the same frequency as the orbit
  • cosmic rays (CR): very-high-energy particles from beyond the solar system
• Crab Nebula (M1): supernova remnant in Taurus
• Crab Pulsar:
  • Crab Nebula (M1): supernova remnant in Taurus
• crab-type remnant:
  • supernova remnant (SNR): nebula of debris resulting from a supernova
• CRaTER:
  • Lunar Reconnaissance Orbiter (LRO): space probe orbiting the Moon
• Crater 2:
  • Milky Way subgroup: the Milky Way and its satellites
• CRATES: catalog of 8.4 GHz data on radio sources
• CRB:
  • cosmic rays (CR): very-high-energy particles from beyond the solar system
• CRIRES: high resolution IR echelle spectrometer
  • European Southern Observatory Very Large Telescope (ESO VLT,VLT): four 8.2-meter optical telescopes in Chile that can act together
• CRIRES+:
  • CRIRES: high resolution IR echelle spectrometer
• CRIS:
  • Advanced Composition Explorer (ACE): satellite collecting solar wind and cosmic rays
• CRISM:
  • Mars Reconnaissance Orbiter (MRO): Mars probe launched by NASA in 2005
• critical density (ρ_c): density of the universe which leaves it flat
• critical density of the universe:
  • critical density (ρ_c): density of the universe which leaves it flat
• critical point:
  • supercritical fluid (SCF): state of matter at sufficient pressure and temperature
• critical radius:
  • circumbinary planet: exoplanet orbiting two stars
• critical rotation:
  • stellar rotation: rotation of a star around an axis through the middle
• critical velocity:
  • stellar rotation: rotation of a star around an axis through the middle
• CRL:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• cross dispersion spectrograph: echelle spectrograph with additional disperser crosswise to the first
• cross Dragone:
  • Dragone telescope: off-axis reflector telescope type that preserves polarization
• cross Dragone telescope:
  • Dragone telescope: off-axis reflector telescope type that preserves polarization
• cross section: "area" representation of probability of an interaction of particles
• crossed-Dragone design:
  • Dragone telescope: off-axis reflector telescope type that preserves polarization
• crowdsource:
  • Galaxy Zoo: crowdsourcing website to identify galaxy types from surveys
  • Galaxy Zoo 2 (GZ2): crowd-sourced classification of hundreds of thousands of galaxies
  • Planet Hunters (PH): crowdsourcing website to identify galaxy types from surveys
• CRS:
  • Voyager: space probes to observe planets and the edge of the solar system
• CRTS:
  • Catalina Sky Survey (CSS): survey of near-Earth objects
• crust:
  • load density: measure of rigidity of the crust of a body
• crustal magnetism: magnetic fields independent of a world's core magnetic field
• crustal plates: sections of the Earth's crust that move
• cryogenic:
  • cryogenic spectroscopy: laboratory spectroscopy of materials cooled to cryogenic temperatures
• Cryogenic Infrared Echelle Spectrometer:
  • CRIRES: high resolution IR echelle spectrometer
• cryogenic spectroscopy: laboratory spectroscopy of materials cooled to cryogenic temperatures
• cryolava:
  • cryovolcano: eruption of substances that are liquid or gas at cold temperatures
• cryovolcanism:
  • cryovolcano: eruption of substances that are liquid or gas at cold temperatures
• cryovolcano: eruption of substances that are liquid or gas at cold temperatures
• crystal ice:
  • snow line: distance from protostar cool enough for water to condense
• crystal nucleation:
  • supercooling: cooling water below freezing point without it freezing
• crystal nucleus:
  • supercooling: cooling water below freezing point without it freezing
• crystalline ice:
  • ice: solid state of water
• CS:
  • tracer: chemical whose presence indicates the presence of another chemical
• CS60:
  • High Altitude Observatory (HAO): NCAR unit observing and monitoring the Sun
• CSA: includes astronomical research
  • James Webb Space Telescope (JWST): future space-based 6.5 meter infrared telescope
  • MOST: 2000s observatory-satellite looking for stellar oscillations
  • NEOSSat: small spacecraft tracking NEOs
• CSE:
  • asymptotic giant branch (AGB): a second stage of helium burning in some stars
  • planetary nebula (PN): gas shell ejected by a red giant
• CSHELL:
  • IRTF: Mauna Kea 3-meter infrared telescope
• CSI:
  • Carl Sagan Institute (CSI): group researching finding life on other planets and moons
  • Catalog of Stellar Identifications (CSI): 1970s catalog cross referencing existing star catalogs
• CSIRO:
  • ATNF Pulsar Catalogue: online catalog of pulsars
  • Australia Telescope Compact Array (ATCA): radio telescope in eastern Australia
• CSM:
  • superluminous supernova (SLSN): stellar explosion larger than a supernova
• CSMF:
  • conditional stellar mass function (CSMF): function characterizing galaxies within a halo of a given mass
• CSN:
  • stellar nucleus: group of many stars at the center of a galaxy
• CSO:
  • Caltech Submillimeter Observatory (CSO): 10.4 meter submillimeter telescope in Hawaii
  • Mauna Kea: Hawaiian mountain, the site of observatories
  • Mauna Kea Observatories (MKO): observatories on Mauna Kea in Hawaii
• CSO-JCMT interferometer:
  • Caltech Submillimeter Observatory (CSO): 10.4 meter submillimeter telescope in Hawaii
• CSP:
  • Carnegie Supernova Project (CSP): survey of supernovae lightcurves
• CSPN:
  • planetary nebula (PN): gas shell ejected by a red giant
• CSPNe:
  • planetary nebula (PN): gas shell ejected by a red giant
• CSS:
  • Catalina Sky Survey (CSS): survey of near-Earth objects
  • Hubble Space Telescope (HST): observatory-satellite with 2.4 meter reflective telescope
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CSV:
  • New Catalogue of Suspected Variable Stars (NSV): catalog from latter half of 20th century catalog
• CT scan:
  • tomography: observation of sections of a 3D object
• CTA:
  • Cherenkov Telescope Array (CTA): ground gamma-ray telescope array in development
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CTB:
  • rare designator prefixes: designator prefixes generally used for only a few objects
• CTIO:
  • Calán/Tololo Survey: late 1980s to early 1990s search to redshift 0.1
  • Cerro Tololo Inter-American Observatory (CTIO): NOAO observatory in Chile with Blanco telescope
  • CTIO Upper-Scorpius OB Association Survey (UScoCTIO): survey of low-mass stars and brown dwarfs
  • Dark Energy Survey (DES): survey aimed at mapping the universe's expansion
  • DECaLS: survey imaging part of SDSS footprint with DECam
  • Deep Lens Survey (DLS): investigating mass distribution of the universe
  • Kitt Peak National Observatory (KPNO): NRAO observatory in Arizona with Mayall telescope
  • Multiwavelength Survey by Yale-Chile (MUSYC): optical/NIR survey of four deep fields
  • National Optical Astronomy Observatory (NOAO): US optical astronomy organization
  • NOAO Deep Wide-field Survey (NDWFS): survey investigating large scale structure of the universe
  • SOAR: 4.1 m reflector telescope in Chile
  • USNO Twin Astrograph: USNO astrograph deployed in 1970
  • Víctor M. Blanco Telescope: 4 m reflector telescope in Chile
• CTIO 1.5m:
  • Cerro Tololo Inter-American Observatory (CTIO): NOAO observatory in Chile with Blanco telescope
  • CTIO Upper-Scorpius OB Association Survey (UScoCTIO): survey of low-mass stars and brown dwarfs
  • SIMP: 2000s infrared proper-motion survey
  • The Survey for Ionization in Neutral Gas Galaxies (SINGG): survey of H-alpha in galaxies found through the HI line
• CTIO Schmidt Camera:
  • Cerro Tololo Inter-American Observatory (CTIO): NOAO observatory in Chile with Blanco telescope
  • CTIO Upper-Scorpius OB Association Survey (UScoCTIO): survey of low-mass stars and brown dwarfs
  • The Survey for Ionization in Neutral Gas Galaxies (SINGG): survey of H-alpha in galaxies found through the HI line
• CTIO Upper-Scorpius OB Association Survey (UScoCTIO): survey of low-mass stars and brown dwarfs
• CTTS:
  • T-Tauri star (TTS): type of variable pre-main-sequence star
• CTX:
  • Mars Reconnaissance Orbiter (MRO): Mars probe launched by NASA in 2005
• cubewano:
  • Kuiper Belt (K Belt,KB): further part of solar system beyond Neptune
• Curiosity:
  • Mars: well-explored planet in the solar system
  • Mars 2020: Mars rover launched in July 2020 and on its way
  • Mars Science Laboratory (MSL): mission to Mars with rover
  • MMRTG: power source for space probes
• curl:
  • mathematical field: function of three variables, potentially representing space
  • Poisson's equation: relates one function's Laplacian to another function
  • vortensity: ratio of vorticity to mass density
  • vortex: fluid region where the flow is spinning
• current:
  • siemens (S): SI unit of electrical conductance
• current sheet: narrow sheet within a magnetic field where current flows
• Curtis-Shapley Debate:
  • Great Debate: historical debate regarding the nature of galaxies
• curvature: unflatness of space
  • wormhole: connection between two regions in a curved space
• curvature fluctuation amplitude:
  • Lambda-CDM model (ΛCDM,LCDM): Big-Bang cosmological model with a cosmological constant and cold dark matter
• curvature radiation: synchrotron-like radiation when particles follow curved field lines
• curvature scalar:
  • curvature: unflatness of space
• curvature sensor:
  • wavefront sensor: instrument for determining a wave's deformation
• curve of growth:
  • line broadening: processes causing a spectral line to have width
• curved space:
  • curvature: unflatness of space
• cusp:
  • core-cusp problem: theories and observation show different dwarf galaxy rotation curves
• cut-off frequency:
  • thermal bremsstrahlung: type of EMR produced by thin, hot plasma
• CV:
  • cataclysmic variable star (CV): star whose magnitude is much brighter on occasion
• CvB:
  • cosmic background radiation (CBR): electromagnetic radiation coming from every direction
• CVZ:
  • continuous viewing zone (CVZ): region of sky that can be viewed 7×24×365
• CWFM:
  • frequency modulation (FM): changing the frequency of a signal's carrier
• CWI:
  • Hale Telescope: 5.1 m reflector telescope in California
• CXB:
  • cosmic background radiation (CBR): electromagnetic radiation coming from every direction
  • cosmic X-ray background (CXB,CXRB,CXBR): X-ray radiation coming from outside the Milky Way
• CXBR:
  • cosmic X-ray background (CXB,CXRB,CXBR): X-ray radiation coming from outside the Milky Way
• CXC:
  • Chandra X-ray Observatory (CXO): space X-ray telescope
• CXE:
  • HEAO-1: 1977 X-ray observatory space mission
• CXO:
  • Chandra X-ray Observatory (CXO): space X-ray telescope
• CXOU:
  • Chandra X-ray Observatory (CXO): space X-ray telescope
• CXRB:
  • cosmic X-ray background (CXB,CXRB,CXBR): X-ray radiation coming from outside the Milky Way
• Cybele:
  • asteroid family: set of asteroids based on similar orbits
• cycloalkane:
  • hydrocarbon (HC): any compound of just carbon and hydrogen
• cyclotron:
  • cyclotron radiation: radiation emitted when charged particles are accelerated
• cyclotron frequency:
  • cyclotron radiation: radiation emitted when charged particles are accelerated
• cyclotron radiation: radiation emitted when charged particles are accelerated
  • electron scattering: any process that changes the course of an electron
• Cygnus A (3C 405,QSO B1957+405): early-discovered radio galaxy and quasar
• Cygnus OB2-12:
  • hypergiant: extremely bright stars
• Cygnus X Star Forming Region:
  • Dickel-Wendker-Bieritz Catalog (DWB): list of HII regions in the Cygnus X star forming region
• cylindrical radio telescope:
  • cylindrical telescope: telescope with cylindrical reflectors
• cylindrical telescope: telescope with cylindrical reflectors
• Cz:
  • Czernik Catalog (Cz): list of open clusters
• Czernik:
  • Czernik Catalog (Cz): list of open clusters
• Czernik Catalog (Cz): list of open clusters
• Czernik Open Cluster Catalogue:
  • Czernik Catalog (Cz): list of open clusters