Term Index (S)
- S:
- entropy (S): relative measure of the amount of usable energy available
- Poynting vector (S): measures directional energy flux density
- sensitivity function (S): function of wavelength giving the sensitivity of an instrument
- source function (S): measure indicating the effect of a material on EMR passing through
- spectral flux density (S): flux or power of radiation per unit area per unit wavelength
- sulfur (S): metal, S, atomic number 16
- S orbital:
- Sérsic index:
- Sérsic profile: model of the relative surface brightness across a galaxy
- Sérsic law:
- Sérsic profile: model of the relative surface brightness across a galaxy
- Sérsic model:
- Sérsic profile: model of the relative surface brightness across a galaxy
- Sérsic profile: model of the relative surface brightness across a galaxy
- S-class:
- red giant: reddish, giant late stage of stellar evolution
- S-type star: type of star with lines indicating zirconium
- S-index:
- s-process: synthesization of elements through neutron capture and beta decay
- S-star:
- S-type star: type of star with lines indicating zirconium
- S-type star: type of star with lines indicating zirconium
- S/N:
- S5:
- SA:
- SAAO:
- SAB:
- Sachs-Wolfe effect (SWE,SWeffect): gravitational redshift of the CMB
- SAFARI:
- SPICA: plan for a future space IR telescope
- SagDIG:
- SAGE: survey of gas and dust in the Magellanic Clouds
- SAGE-LMC:
- SAGE: survey of gas and dust in the Magellanic Clouds
- SAGE-SMC:
- SAGE: survey of gas and dust in the Magellanic Clouds
- SAGE-Spec:
- SAGE: survey of gas and dust in the Magellanic Clouds
- Sagittarius A*:
- Sagittarius Dwarf Elliptical Galaxy (Sgr dE): satellite galaxy of the Milky Way
- Sagittarius Dwarf Irregular Galaxy (SagDIG): most distant galaxy in the Local Group
- Sagittarius Dwarf Spheroidal Galaxy:
- Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS): transit search using HST time
- Sagittarius-Carina Arm:
- spiral arm: long, winding visible structure within a spiral galaxy
- Saha equation: equation relating ionization to temperature
- Saha ionization equation:
- Saha-Langmuir equation:
- Saiph:
- Orion: well-known constellation in the northern hemisphere
- Salpeter function:
- Salpeter IMF:
- Salpeter time:
- Salpeter timescale: timescale for black hole growth
- SALT:
- SALTICAM:
- SAM:
- SAMI:
- Sample Acquisition System:
- CAESAR: planned space mission to return a sample of a comet
- Samuel Oschin Telescope:
- Santa Cruz:
- SAO:
- SAO Star Catalog: 1960s catalog
- SAO/ASIAA:
- SAO/NASA Astrophysics Data System:
- Sardinia Radio Telescope (SRT): Italian large single-dish radio telescope
- SAS:
- CAESAR: planned space mission to return a sample of a comet
- SAS 1:
- Uhuru: 1970 satellite X-ray telescope
- SAS-A:
- Uhuru: 1970 satellite X-ray telescope
- SASSy:
- SCUBA: submillimeter instrument on James Clark Maxwell Telescope
- satellite:
- exosatellite: natural satellite not in the solar system
- moon: a planet's natural satellite, such as Earth's
- satellite galaxies:
- satellite galaxy: galaxy that orbits a larger galaxy
- saturation:
- humidity: amount of water vapor in a portion of the atmosphere
- hydrocarbon (HC): any compound of just carbon and hydrogen
- Saturn: second largest planet in the solar system
- Cassini: explorer spaceship sent to Saturn
- Dragonfly: plan for Titan flying rover
- Enceladus: Saturn moon considered possible carrier of life
- Enceladus Life Finder (ELF): mission to search for life on Saturn moon Enceladus
- giant planet: planet of more than 10 Earth masses
- gravity sounding: measuring a planet's gravitation field by study of nearby probe flights
- helium rain: possible source of heat in giant planet atmospheres
- ring system: disk or set of rings orbiting a planet
- shepherd moon: small moon at outer edge of a ring
- TAM: non-gray-RT 3D model of Titan's atmosphere
- Titan: well-known Saturn moon
- Voyager: space probes to observe planets and the edge of the solar system
- Saturn II:
- Enceladus: Saturn moon considered possible carrier of life
- Saturn V:
- Space Launch System (SLS): launch rocket in development, e.g., for future astronomical projects
- Saturn VI:
- Titan: well-known Saturn moon
- SAURON:
- SB:
- SBB:
- Big Bang: theoretical event when the universe expanded from a point
- SBF:
- SBH:
- SBIG STX-6303:
- SBS:
- SBS 0335-052: blue compact galaxy
- scalar boson:
- scalar curvature:
- scalar field:
- scalar spectral index:
- Lambda-CDM model (ΛCDM,LCDM): Big-Bang cosmological model with a cosmological constant and cold dark matter
- scale:
- scale factor (a): relative size of the universe as a function of time
- scale height (H): measure of exponential falloff
- scan pattern:
- scan speed: the speed at which the telescope changes angle on the sky while observing
- scandium:
- Am star: A-type star with metallic lines
- SCARLET:
- scattering coefficient:
- SCExAO:
- Schönberg-Chandrasekhar limit: maximum stellar isothermal helium core mass
- Schechter function:
- luminosity function (LF): function giving number of stars or galaxies at different luminosities
- Schechter luminosity function:
- luminosity function (LF): function giving number of stars or galaxies at different luminosities
- Schiefspiegler: type of off-axis reflecting telescope
- Schmidt camera: telescope type with a very wide field of view
- Schmidt corrector plate:
- Schmidt law:
- Schmidt Oschin Telescope:
- Schmidt telescope:
- Schmidt-Newton telescope: type of reflecting telescope
- Schmidt-Newtonian telescope:
- Scholz's Star: nearby binary star with red dwarf and brown dwarf
- Schuster-Schwarzschild model: approximation of a star's internal EMR's divergence from isotropic
- Schwarzschild black hold:
- Schwarzschild density:
- Schwarzschild diameter:
- Schwarzschild metric:
- metric: mathematical generalization of the concept of distance
- Schwarzschild radius: radius of a black hole's event horizon
- event horizon (EH): surface-shape around a black hole through which light cannot escape
- Schwarzschild throat:
- wormhole: connection between two regions in a curved space
- Schwarzschild wormhole:
- wormhole: connection between two regions in a curved space
- science:
- Science Run:
- LIGO: pair of observatories to detect gravitational waves
- scintillation:
- scintillometer:
- scintillometry: measuring of twinkling
- SCl 117:
- SCl 128:
- SCl 40:
- SCM:
- THEMIS: set of satellites studying the Earth's magnetic field
- Scorpius-Centaurus Association:
- Scott effect: bias toward finding clusters that have bright galaxies
- SCP:
- SCR:
- SCUBA: submillimeter instrument on James Clark Maxwell Telescope
- SCUBA-1:
- SCUBA: submillimeter instrument on James Clark Maxwell Telescope
- SCUBA-2:
- SCUBA-2 All Sky Survey:
- SCUBA: submillimeter instrument on James Clark Maxwell Telescope
- SCUBA-2 Ambitious Sky Survey:
- SCUBA: submillimeter instrument on James Clark Maxwell Telescope
- Sculptor Galaxy:
- NGC 253: spiral galaxy 11 million light-years away
- Sculptor Void:
- Sculptor Wall: large slab of galaxies
- Scutum-Centaurus Arm: one of two spiral galaxy arms from the Milky-Way bar
- spiral arm: long, winding visible structure within a spiral galaxy
- Scutum-Crux Arm:
- SD2:
- Rosetta: space probe that visited a comet
- SDC:
- SDF:
- Subaru Deep Field (SDF): survey of a small region of the sky using the Subaru telescope
- SDI:
- SDO:
- SDSS:
- search for extraterrestrial intelligence:
- Search for Habitable Planets Eclipsing Ultra-cool Stars:
- SPECULOOS: search for Earth-like exoplanets orbiting nearby dim stars
- sec:
- arcsecond (arcsec,sec): a 3600th of an angular degree
- SECCHI:
- STEREO: two-satellite system to observe the Sun
- second:
- arcsecond (arcsec,sec): a 3600th of an angular degree
- Second Byurakan Survey (SBS): 1970s-1990s survey of galaxies and quasars
- second order perturbation problem:
- Second Palomar Observatory Sky Survey:
- secondary eclipse: eclipse of a body that also transits
- secondary mirror:
- secular: occurring slowly over a long period of time
- Laplace radius (rL): a radius for a stable orbit of a satellite around a planet
- secular GI:
- secular gravitational instability:
- secular motion:
- secular: occurring slowly over a long period of time
- secular parallax:
- parallax: angle due to different lines of sight
- secular resonance:
- secular variation:
- secular: occurring slowly over a long period of time
- SED:
- SED fitting:
- SEDS:
- seeing: apparent blurring and twinkling of objects seen through atmosphere
- seeing limited:
- diffraction limited: telescope limited only by the laws of diffraction
- seeing: apparent blurring and twinkling of objects seen through atmosphere
- seeing number:
- seeing: apparent blurring and twinkling of objects seen through atmosphere
- segmented mirror: a telescope mirror formed of array of smaller mirrors
- Segue:
- SEGUE-2:
- seismic waves: waves broadcast from earthquakes
- seismology:
- selectron:
- SELENE: 2007-2008 Japanese lunar probe
- Selenological and Engineering Explorer:
- SELENE: 2007-2008 Japanese lunar probe
- semi-analytic model (SAM): cosmological model combining analytic and other methods
- semi-major axis (a): maximum radius of an ellipse
- semi-minor axis:
- semiconductor detector:
- semidetached binary:
- semimajor axis:
- sensitivity function (S): function of wavelength giving the sensitivity of an instrument
- SEP:
- SEPICA:
- SEQUELS:
- SEQUOIA:
- SERC:
- IRAS: 1983 satellite that surveyed the sky in infrared
- UK Schmidt Survey: photographic survey of the southern hemisphere sky
- Serpens Cloud: molecular cloud with SF regions
- Serpens Main:
- Serpens Molecular Cloud:
- Serpens South:
- Serrurier truss:
- SERVS:
- SESAME:
- Rosetta: space probe that visited a comet
- Set of Identifications:
- SIMBAD: online database of astronomical objects
- SETI:
- SETI Institute:
- Seyfert:
- Seyfert galaxy: visible active galaxy
- SF:
- SF main sequence:
- SF rate:
- SF region:
- SFE:
- SFG:
- SFH:
- SFH Camera:
- CCAT-prime (CCAT-p): planned 6 meter submillimeter telescope in Chile
- SFM:
- SFR:
- SFRD:
- SFRG:
- SGB:
- SGD:
- ASTRO-H: Japanese space X-ray telescope
- SGL:
- SGR:
- Sgr dE:
- Sgr DEG:
- Sgr dSph:
- SGR Dwarf:
- Sgr I Dwarf:
- SGRB:
- gamma-ray burst (GRB): short flashes of gamma rays apparently from outside our galaxy
- GW170817: gravitational wave detection from a neutron star merger
- SGW:
- Sh2:
- Shack-Hartmann sensor:
- Shakura-Sunyaev disk:
- shallow atmosphere models:
- Shane Telescope:
- SHARAD:
- Sharpless Catalog (Sh2): catalog of HII regions found on Palomar plates
- shearing box: method of simulating 3D MHD in disks
- SHELA:
- shell flash:
- shepherd moon: small moon at outer edge of a ring
- shepherding moon:
- SHERLOC:
- shielding effect:
- SHJ:
- shock:
- shock wave: abrupt propagating disturbance in a fluid
- shock capture scheme:
- shock front:
- shock wave: abrupt propagating disturbance in a fluid
- shock heating:
- shock wave: abrupt propagating disturbance in a fluid
- shock tracer:
- shock wave: abrupt propagating disturbance in a fluid
- shock wave: abrupt propagating disturbance in a fluid
- short gamma ray burst:
- gamma-ray burst (GRB): short flashes of gamma rays apparently from outside our galaxy
- short Rossby wave:
- Kelvin waves: pressure and gravity waves formed by Coriolis force and a barrier
- short-period comet:
- shot noise:
- photon noise: variation in light measurement due to its quantum nature
- shot noise level:
- photon noise: variation in light measurement due to its quantum nature
- SI: modern metric system
- CGS: metric system variant
- joule: SI unit of energy
- magnetic flux (B): total magnetism passing through a surface
- magnetic flux density (B): vector field describing magnetism in relation to the Lorentz force
- silicon (Si): metal, Si, atomic number 14
- sulfur (S): metal, S, atomic number 16
- tesla (T): unit of magnetic flux density
- watt (W): SI unit of power
- sidereal: relative to the fixed position of the stars
- sidereal day:
- sidereal: relative to the fixed position of the stars
- solar time: time based upon the position of the Sun in the Earth's sky
- sidereal month:
- sidereal: relative to the fixed position of the stars
- sidereal period:
- orbital period: length of time for an orbiting object to complete one cycle
- synodic period: period until a planet returns to the same position relative to the Sun
- sidereal time:
- solar time: time based upon the position of the Sun in the Earth's sky
- sidereal year:
- sidereal: relative to the fixed position of the stars
- siderophile: material that dissolves in molten iron
- siderophile element:
- Siding Spring Observatory:
- SIGMA:
- GRANAT: observatory-satellite for detecting gamma rays and X-rays
- sigma (σ): indication of the confidence level of an experiment
- signal:
- signal-to-noise ratio (SNR,S/N): ratio of the power of a signal to the power of the background noise
- signatures of formation: qualities of a body that suggest how it was formed
- SII:
- sulfur (S): metal, S, atomic number 16
- silica:
- basalt: an igneous rock type that shows rapid cooling
- geochemistry: the chemistry of the Earth, planets, and moons
- silicate: type of compound including silicon and oxygen
- silicon (Si): metal, Si, atomic number 14
- silicon burning:
- silicon (Si): metal, Si, atomic number 14
- silicon dioxide:
- Silver Coin Galaxy:
- NGC 253: spiral galaxy 11 million light-years away
- Silver Dollar Galaxy:
- NGC 253: spiral galaxy 11 million light-years away
- SIMBAD: online database of astronomical objects
- Simons Array:
- Simons Observatory: planned astronomy facility on Atacama Desert for ACT and other telescopes
- Simons Observatory: planned astronomy facility on Atacama Desert for ACT and other telescopes
- SIMPLE:
- SIMSTACK: software to correlate intensity maps with sources
- simulation:
- AREPO: cosmology simulation using moving mesh technique
- AstroBEAR: MHD simulation system
- Bolshoi simulation: cosmological simulation
- Castro: hydrodynamics simulation software
- Cloudy: code to model the affect of gas and plasma on spectra
- EAGLE: simulation of galaxy formation and evolution
- Enzo: hydrodynamic simulation system
- FIRE Simulations: high resolution simulation of galaxies
- FLASH: hydrodynamic simulation system
- FORNAX: hydrodynamics simulation software
- GADGET-2: an n-body/SPH simulation computer program
- GR1D: core collapse supernova simulation in 1D with GR
- Hyperion: Monte Carlo radiative transfer code
- Illustris Project: 2013-2015 series of cosmological simulations
- Monte Carlo method: mathematics and simulation using random samples
- PLUTO Code: fluid-dynamic simulation code
- PROMETHEUS/VERTEX: hydrodynamic simulation system
- RAMSES: hydrodynamic simulation system
- random walk: movement with random turns
- RHAPSODY: simulation of galaxy cluster dark-matter halos
- STARBURST99: software to simulate star-forming galaxies
- Turtlebeach: radiative transfer code
- simulations:
- simultaneity:
- relativity: physics models accommodating the constancy of the speed of light
- SINFONI:
- single-line spectroscopic binary:
- single-object slitless spectroscopy:
- singly ionized carbon:
- C+: ionized carbon missing one electron
- singular perturbation problem:
- singularity:
- black hole (BH): region of such high mass that light cannot escape
- SINS: near-infrared study of distant luminous galaxies
- SINS/zC-SINF:
- SINS: near-infrared study of distant luminous galaxies
- Sinstro:
- Sirius: brightest star in the sky
- Am star: A-type star with metallic lines
- Sirius A:
- Sirius: brightest star in the sky
- Sirius B:
- Sirius: brightest star in the sky
- SIRTF:
- SIS:
- site:
- arXiv.org: website with physics paper preprints
- Astrophysics Data System (ADS): website with astrophysics bibliography and paper archive
- ExoFOP: site to facilitate exoplanet follow-up observation
- Galaxy Zoo: crowdsourcing website to identify galaxy types from surveys
- Galaxy Zoo 2 (GZ2): crowd-sourced classification of hundreds of thousands of galaxies
- HEASARC: archive of NASA data on high energy astronomy
- IRSA: archive center for infrared data from NASA missions
- LAMBDA: NASA archive center re CMB data
- MAST: archive of data from surveys and missions
- NASA/IPAC Extragalactic Database (NED): a database of galaxies and other objects outside the Milky Way
- Planet Hunters (PH): crowdsourcing website to identify galaxy types from surveys
- SIMBAD: online database of astronomical objects
- SITELLE:
- SKA:
- SKA1:
- SKA1-low:
- SKA1-mid:
- SKA2:
- skeleton:
- filament: linear volume of high molecular gas density within a galaxy
- SKHB: survey of globular clusters in M31
- Skumanich law:
- Skumanich relationship:
- sky:
- Baade's Window: region of sky allowing observation into the galactic center
- BDF: field used in search for distant galaxies
- celestial sphere: the sky in considered as a sphere surrounding the observer
- Extended Groth Strip (EGS): region of sky searched for distant galaxies
- Gould's Belt: ring of stars around the sky
- Lockman hole: region of sky with little Milky-Way neutral hydrogen
- Olbers' paradox: argument using the dark of the sky regarding the nature of the universe
- sidereal: relative to the fixed position of the stars
- zone of avoidance (ZOA): region of sky obscured by Milky Way
- sky subtraction: removing background radiation from a telescope observation
- SkyMapper: automated 1.35m optical telescope in Australia
- SkyMapper Southern Sky Survey:
- SkyMapper Southern Survey (SMSS): digital survey of the southern hemisphere sky
- SLED:
- Slepian window function:
- slew: rotating a telescope to point it
- slew survey: survey conducted by imaging during a telescope's repointings
- slew observation:
- slew survey: survey conducted by imaging during a telescope's repointings
- slew survey: survey conducted by imaging during a telescope's repointings
- SLF:
- slide rule:
- slit:
- Sloan 2.5m Telescope: telescope for SDSS in New Mexico
- Sloan Digital Sky Survey (SDSS): imaging survey of 500,000,000 objects in 35% of sky
- Sloan Extended Quasar, ELG, and LRG Survey:
- Sloan Extension for Galactic Understanding and Exploration:
- Sloan Foundation 2.5m Telescope:
- Sloan Great Wall (SGW): large slab of galaxies discovered in SDSS
- slow neutron-capture-process:
- s-process: synthesization of elements through neutron capture and beta decay
- slow quenching:
- slow shock:
- shock wave: abrupt propagating disturbance in a fluid
- SLS:
- SLSN:
- SLSN-I:
- SLSN-II:
- SLSN-R:
- SM:
- SM0313:
- SMA:
- Small Astronomical Satellite 1:
- Uhuru: 1970 satellite X-ray telescope
- Small Explorer Program:
- Small Magellanic Cloud (SMC): dwarf galaxy in the Local Group
- small solar system body:
- minor planet: lesser solar system body without comet characteristics
- SSSB: solar system body smaller than a dwarf planet
- SMBBH:
- SMBH:
- SMBH binary:
- binary SMBH (BSMBH,SMBBH,SMBHB): co-orbiting supermassive black holes
- SMBHB:
- binary SMBH (BSMBH,SMBBH,SMBHB): co-orbiting supermassive black holes
- SMC:
- SMEX:
- SMG:
- SMI:
- SPICA: plan for a future space IR telescope
- SMI-HRS:
- SPICA: plan for a future space IR telescope
- SMI-LRS:
- SPICA: plan for a future space IR telescope
- SMI-MRS:
- SPICA: plan for a future space IR telescope
- Smith Cloud: high-velocity cloud on collision course with Milky Way
- Smith's Cloud:
- Smith Cloud: high-velocity cloud on collision course with Milky Way
- Smithsonian Astrophysical Observatory:
- Smithsonian Astrophysical Observatory Star Catalog:
- SMM:
- smooth migration:
- smoothed-particle hydrodynamics (SPH): computational method for simulating fluid flows
- SMSS:
- SMT:
- smuon:
- SN:
- supernova (SN): stellar explosion larger than a nova
- SN 1972E:
- SN 2014J: type Ia supernova in Messier 82, the Cigar Galaxy
- SN 1987A (1987A): supernova in February 1987 rare for being visible by the naked eye
- SN 2011fe:
- SN 2014DJ:
- SN 2014J: type Ia supernova in Messier 82, the Cigar Galaxy
- SN 2014J: type Ia supernova in Messier 82, the Cigar Galaxy
- SN feedback:
- SNAP:
- WFIRST: proposed space observatory
- SNDM:
- Snell's law: optical principle of refraction
- Snell-Descartes law:
- sneutrino:
- SNF:
- SNfactory:
- SNLS:
- snow line: distance from protostar cool enough for water to condense
- SNR:
- SNU:
- SOAR:
- Sobolev approximation: tractable model used in specific kinds of spectral line analysis
- Sobolev length:
- sodium (Na): metal, Na, atomic number 11
- globular cluster (GC): spherical group of stars orbiting a galaxy
- nitrite (NO2-): ion of a nitrogen atom and two oxygen atoms with extra electron
- SOFI:
- SOFIA: aircraft-based infrared observatory
- soft:
- hardness: measure of the binding energy of a binary
- soft binary:
- hardness: measure of the binding energy of a binary
- soft gamma repeater (SGR): object that produces repeated gamma ray bursts
- soft X-ray:
- X-ray: electromagnetic radiation, wavelength .01 to 10 nanometers
- XEUV: electromagnetic radiation in the range of .15nm-400nm
- soft X-ray, extreme ultraviolet and ultraviolet:
- XEUV: electromagnetic radiation in the range of .15nm-400nm
- softness:
- hardness: measure of the binding energy of a binary
- software:
- AREPO: cosmology simulation using moving mesh technique
- AstroBEAR: MHD simulation system
- Astrocats: software to create and manage an astronomy catalog
- Astronomical Image Processing System (AIPS): software for processing radio astronomy data
- ATLAS Stellar Model: computer model of a stellar photosphere
- Bolshoi simulation: cosmological simulation
- BT-Settl: model atmosphere of small stars and brown dwarfs
- Castro: hydrodynamics simulation software
- CMBFAST: software to calculate CMB anisotropies
- code: astrophysical modeling computer program
- DISORT: simulation of radiative transfer in an atmosphere
- EAGLE: simulation of galaxy formation and evolution
- Enzo: hydrodynamic simulation system
- ExoCTK: collection of software for exoplanet observation and analysis
- FIRE Simulations: high resolution simulation of galaxies
- FLASH: hydrodynamic simulation system
- FORNAX: hydrodynamics simulation software
- GADGET-2: an n-body/SPH simulation computer program
- Glue: visualization software good for astrophysical data
- GR1D: core collapse supernova simulation in 1D with GR
- Hyperion: Monte Carlo radiative transfer code
- IDL: interactive vector-oriented programming language
- LasDamas: simulations of large scale evolution of dark matter and galaxies
- lightkurve: software to analyze time series data
- MITgcm: well-known general circulation model
- OpenSpace: visualization software aimed at astrophysical data
- Partiview: visualization software aimed at 4d data
- PHOENIX stellar model: computer model of a stellar photosphere
- PLUTO Code: fluid-dynamic simulation code
- PROMETHEUS/VERTEX: hydrodynamic simulation system
- RAMSES: hydrodynamic simulation system
- RHAPSODY: simulation of galaxy cluster dark-matter halos
- ROCKE-3D: Rocky-planet-oriented general circulation model
- SIMSTACK: software to correlate intensity maps with sources
- SPECTRE: an interactive spectrum analysis software package
- STARBURST99: software to simulate star-forming galaxies
- StarTrack: stellar population synthesis code
- TAM: non-gray-RT 3D model of Titan's atmosphere
- Turtlebeach: radiative transfer code
- Uniview: planetarium software
- yt: analysis and display software
- software telescope: telescope that depends more than normal upon software for analysis
- software type:
- SOHO:
- Sol:
- Mars: well-explored planet in the solar system
- solar:
- Solar and Heliospheric Observatory (SOHO): satellite observing the Sun
- solar antapex:
- solar apex: direction that the Sun is moving compared to nearby stars
- solar apex: direction that the Sun is moving compared to nearby stars
- solar arcade:
- solar circle: Sun's orbit around the Milky Way
- solar constant: flux from the Sun at 1 AU
- solar cycle:
- dynamo: mechanism for generating magnetic fields around astronomical bodies
- sunspot: temporary darker region of the Sun's surface
- solar day:
- Venus: second inner-most planet in the solar system
- Solar Dynamics Observatory (SDO): 2010 satellite observing the Sun
- solar dynamo:
- dynamo: mechanism for generating magnetic fields around astronomical bodies
- solar energetic particle (SEP): high-energy particles from the Sun
- solar eruption: sudden brightening of the Sun
- solar event:
- solar flare: sudden brightening of the Sun
- solar galactocentric distance:
- solar irradiance:
- insolation: solar energy received per unit area in given time
- solar lithium problem:
- solar luminosities:
- watt (W): SI unit of power
- solar luminosity:
- Sun: star at center of solar system
- watt (W): SI unit of power
- Solar mass:
- mass: object's quality that determines the effects of forces and gravity
- solar mass (MSun,Msun): mass unit representing the mass of the Sun
- Sun: star at center of solar system
- solar maximum:
- sunspot: temporary darker region of the Sun's surface
- Solar Maximum Mission (SMM): 1980s satellite to study the Sun during solar maximum
- solar minimum:
- magnetic field: magnetic force as distributed over a space
- sunspot: temporary darker region of the Sun's surface
- solar motion:
- solar apex: direction that the Sun is moving compared to nearby stars
- solar nebula: cloud of gas and dust that formed the solar system
- solar nebular disk model:
- solar neutrino problem:
- solar neutrino unit (SNU): unit for the detection rate of neutrino detectors
- solar particle event:
- solar prominence:
- solar proton event:
- solar radius:
- Sun: star at center of solar system
- solar seismology:
- solar storm: general term for events on the Sun
- Solar Storm of 1859:
- solar system: the Sun and what's gravitationally bound to it
- anomalous cosmic rays (ACR): cosmic rays with unexpectedly low energies
- asteroid: minor planet without comet characteristics
- asteroid belt: ring of orbiting planetoids/asteroids
- asteroid family: set of asteroids based on similar orbits
- binary minor planet (BMP): minor planet with another body orbiting it
- CAI: calcium/aluminum specs in chondrites
- centaur: asteroid-like body orbiting among the outer planets
- chondrite: stony meteorites showing no melting
- comet: Sun-orbiting object with coma and possible tail
- dwarf planet: round like a planet, only smaller
- Earth: third solar system planet from the Sun
- ephemeris: information on the position of a celestial body in the sky over time
- equilibrium condensation model: chemical model explaining solar system planet abundances
- heliopause: boundary between solar wind and the interstellar medium
- heliosheath: region just beyond the heliosphere
- interplanetary medium (IPM): matter in the solar system around and between planets
- irregular moon: moon with an atypical orbit, such as retrograde
- Jupiter: largest planet in the solar system
- Kuiper Belt (K Belt,KB): further part of solar system beyond Neptune
- late heavy bombardment (LHB): time after solar system planet-formation when many impacts occurred
- long-period comet: comet with an orbital period of more than 200 years
- Mars: well-explored planet in the solar system
- Mercury: inner-most and smallest planet in the solar system
- meteoroid: rocky object in solar system, smaller than an asteroid
- minor planet: lesser solar system body without comet characteristics
- near-Earth object (NEO): object orbiting the Sun that passes close to Earth
- nebular hypothesis: model positing solar system planets result from a solar disk
- Neptune: outer-most solar system planet
- Nice model: model of the evolution of the solar system
- oligarch: term for large planetesimals that dominate
- Oort Cloud: cloud of comets and minor planets around the solar system
- orrery: mechanical device to simulate the solar system
- Outer Solar System Origins Survey (OSSOS): survey searching for trans-Neptune objects
- planet: round object orbiting a star that clears out its own orbital path
- Planet Nine: theoretical planet beyond Neptune
- planetoid: an asteroid or physically similar body
- plutoid: Pluto-like dwarf planet
- provisional designation: way to designate newly discovered solar system objects
- Saturn: second largest planet in the solar system
- solar constant: flux from the Sun at 1 AU
- solar nebula: cloud of gas and dust that formed the solar system
- solar wind: charged particles emanating from the Sun
- SPACEWATCH: survey to study minor planets
- SSSB: solar system body smaller than a dwarf planet
- star system: a star and what's gravitationally bound to it
- Sun: star at center of solar system
- trans-Neptunian object (TNO): minor planet beyond Neptune
- Uranus: second outer-most solar system planet
- Venus: second inner-most planet in the solar system
- Voyager: space probes to observe planets and the edge of the solar system
- solar system ephemerides:
- ephemeris: information on the position of a celestial body in the sky over time
- Solar Terrestrial Relations Observatory:
- STEREO: two-satellite system to observe the Sun
- solar time: time based upon the position of the Sun in the Earth's sky
- solar wind: charged particles emanating from the Sun
- Advanced Composition Explorer (ACE): satellite collecting solar wind and cosmic rays
- aurora: light produced by atmosphere and solar wind
- heliopause: boundary between solar wind and the interstellar medium
- heliosheath: region just beyond the heliosphere
- Voyager: space probes to observe planets and the edge of the solar system
- SOLAR-A:
- Solar-flux monitor:
- solid angle (Ω): two-dimensional analog of an angle
- field of view (FOV): angular measure of how much an optical instrument can view
- solid state detector:
- solstice: moment when Sun reaches its northern- or southern-most position
- Soltan argument: distant quasars imply SMBHs still exist
- Sombrero Galaxy (M104): striking spiral galaxy with very large bulge
- sonic Mach number:
- SOSS:
- sound:
- sound speed: speed at which compression waves traverse a gas
- sound speed: speed at which compression waves traverse a gas
- source:
- radio source (RS): something in the sky generating radio signal
- source counts:
- source function (S): measure indicating the effect of a material on EMR passing through
- South Africa:
- South African Astronomical Observatory:
- south node:
- South Pole:
- BICEP2: survey to measure the polarization of the CMB
- CMB Stage-4 (CMB-S4): planned 2020s-generation of ground CMB observations
- IceCube: neutrino detector at the South Pole
- South Pole Telescope (SPT): a microwave to radio telescope at South Pole
- South Pole Station:
- BICEP2: survey to measure the polarization of the CMB
- South Pole Telescope (SPT): a microwave to radio telescope at South Pole
- Southern African Large Telescope (SALT): 10 meter telescope in South Africa
- Southern Astrophysical Research Telescope:
- Southern Great Wall:
- Southern Sky Atlas:
- Southern Sky Survey:
- Southern Supercluster:
- Southern Wall:
- southern zone of avoidance:
- space:
- Space Infrared Telescope Facility:
- Space Infrared Telescope for Cosmology and Astrophysics:
- SPICA: plan for a future space IR telescope
- Space Launch System (SLS): launch rocket in development, e.g., for future astronomical projects
- Space Shuttle:
- Space Surveillance Telescope:
- LINEAR: survey of near-Earth objects
- Space Telescope Science Institute (STScI): science operator of space telescopes
- space weathering:
- weathering: changes in surface due to contact with atmosphere
- space-like:
- geodesic: equivalent to a straight line in curved space
- spacetime diagram: graph of simplified spacetime, with fewer space dimensions
- spacecraft:
- spacetime: four dimensions: time and the three space dimensions
- curvature: unflatness of space
- geodesic: equivalent to a straight line in curved space
- worldline: path of an object through space and time
- spacetime diagram: graph of simplified spacetime, with fewer space dimensions
- spacetime interval:
- SPACEWATCH: survey to study minor planets
- Spacewatch 1.8-m telescope:
- Spain:
- CALIFA: spectroscopic map of 600 galaxies
- GISMO: 2 mm bolometer camera on IRAM 30m telescope
- IRAM 30m Telescope: millimeter-range radio telescope in Sierra Nevada, Spain
- SPARC:
- MITgcm: well-known general circulation model
- SPARC-MITgcm:
- MITgcm: well-known general circulation model
- spatial correlation function:
- spatial direction:
- spatial resolution:
- SPD:
- SPE:
- SpEC: code to solve general relativity problems
- special relativity:
- Lorentz transformation: equations describing the effect of relative motion on length and velocity
- mass: object's quality that determines the effects of forces and gravity
- relativity: physics models accommodating the constancy of the speed of light
- spacetime: four dimensions: time and the three space dimensions
- specific angular momentum (J): absolute angular momentum divided by mass
- specific heat: ratio of added temperature to added heat for a material
- specific heat capacity:
- specific heat: ratio of added temperature to added heat for a material
- specific humidity:
- humidity: amount of water vapor in a portion of the atmosphere
- specific intensity:
- intensity: power reaching a surface from a specific source
- specific star formation rate:
- specific volume: ratio of volume to mass
- specification:
- angular resolution: measure of a telescope's ability to distinguish spatial detail
- elevation range: measure of how high and low a telescope can be pointed
- emissivity: measure of a material's efficiency at radiating thermal radiation
- exit pupil: size of the image as presented to the eye
- field of view (FOV): angular measure of how much an optical instrument can view
- Fsky (fsky): fraction of the sky, e.g., what a survey covers
- pointing error (PE): discrepancy in telescope's aim
- scan speed: the speed at which the telescope changes angle on the sky while observing
- sensitivity function (S): function of wavelength giving the sensitivity of an instrument
- spectral resolution: measure of a spectrograph's ability to resolve features of the spectrum
- Strehl ratio: measure of optical aberration
- wavefront error (WFE): measure of a telescope's distortion of incoming waves
- speckle noise:
- speckle suppression: methods of reducing noise in telescope observations
- spectral band: set of related, closely-packed spectral lines
- spectral class: classification of spectrums of stars (O, B, A, etc.)
- spectral classification:
- spectral correlator: correlator that also functions as a spectrograph
- spectral density: strength of power or energy as a function of frequency
- spectral differential imaging:
- spectral direction:
- Spectral Einstein Code:
- SpEC: code to solve general relativity problems
- spectral energy distribution (SED): function or plot of brightness at each wavelength in the spectrum
- spectral energy distribution fitting:
- spectral feature: recognizable feature of a spectrum
- spectral feature extraction:
- spectral flux:
- spectral flux density (S): flux or power of radiation per unit area per unit wavelength
- spectral index (α): power by which an object's flux depends on frequency
- spectral line: dark or light line in a spectrum
- spectral line energy distribution (SLED): function or plot of brightness of lines in a spectrum
- spectral line shape:
- spectral method: method of numerically solving differential equations
- spectral photometry:
- photometry: studying starlight through bandpass filters
- spectral photon distribution:
- spectral power distribution (SPD): function of power versus wavelength or frequency
- spectral radial velocity:
- spectral radiance:
- intensity: power reaching a surface from a specific source
- radiance: measure of EMR to/from a solid angle through and area
- radiative transfer (RT): energy transfer in the form of electromagnetic radiation
- spectral resolution: measure of a spectrograph's ability to resolve features of the spectrum
- spectral retrieval:
- retrieval: determining measures through observation and modeling
- spectral signature: spectral characteristics indicating the emitting material and conditions
- spectral type:
- A-type star (A): type of star with about 2 times the mass of the Sun
- B-type star (B): type of star with about 10 times the mass of the Sun
- F-type star (F): type of star with about 1.5 times the mass of the Sun
- FGK star: a star of class F, G, or K
- G-type star (G): stars similar to the Sun
- K-type star (K): type of star with about 3/4 the mass of the Sun
- L-type star (L): type of star cooler than an M-type star
- M-type star (M): type of star with a temperature in the vicinity of 2500K
- O-type star (O): type of star with about 50 times the mass of the Sun
- O5 spectral class (O5): type of star with about 50 times the mass of the Sun
- OB star: a hot star with class O or B
- S-type star: type of star with lines indicating zirconium
- spectral class: classification of spectrums of stars (O, B, A, etc.)
- T-type star (T): type of dwarf with a temperature in the vicinity of 1000K
- Y-type star (Y): type of dwarf with a temperature less than 700K
- spectral-line mapping:
- SPECTRE: an interactive spectrum analysis software package
- Spectro-photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer:
- SPHEREx: all-sky spectral survey space-mission plan
- Spectro-polarimetric High-contrast Exoplanet Research:
- SPHERE: VLT instrument for imaging exoplanets
- spectro-z:
- 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
- spectrometers:
- spectrometry: measuring the strengths of different electromagnetic wavelengths
- spectropolarimeter:
- Spectropolarimeter for Planetary Exploration:
- SpeX: a medium-resolution infrared spectrograph
- spectroscope: device to study the spectrum of incoming light
- 4MOST: planned spectrograph for VISTA telescope
- spectrometer: device to measure light by wavelength across its spectrum
- spectroscopy: measurement of the strengths of different electromagnetic wavelengths
- STARFIRE: planned balloon-borne 2.5m telescope and spectroscope
- spectroscopic binary: binary star detected by movement indicated by Doppler shifts in the spectrum
- Spectroscopic Imaging Survey in the Near-infrared with SINFONI:
- SINS: near-infrared study of distant luminous galaxies
- spectroscopic parallax: stellar distance determined through spectroscopy
- spectroscopic phase curve:
- phase curve: brightness of an object according to its phase angle
- spectroscopic redshift:
- spectroscopic retrieval:
- retrieval: determining measures through observation and modeling
- Spectroscopic Terahertz Airborne Receiver for Far-infrared Exploration:
- STARFIRE: planned balloon-borne 2.5m telescope and spectroscope
- spectroscopy: measurement of the strengths of different electromagnetic wavelengths
- spectrograph: device to record the spectrum of incoming light
- spectrometer: device to measure light by wavelength across its spectrum
- spectroscope: device to study the spectrum of incoming light
- spectrum:
- absorption line: dark line in a spectrum
- Balmer jump: abrupt change in stellar spectrum at end of Balmer series
- Balmer series: hydrogen lines for electrons settling from n > 2 to n = 2
- Brackett series: hydrogen lines for electrons settling from n > 4 to n = 4
- continuous absorption: the absorption of a whole section of a spectrum
- continuous spectrum: smooth spectrum or portion of spectrum with no lines
- emission line: point of high intensity in a spectrum
- extreme ultraviolet (EUV,XUV): electromagnetic radiation in the range of 10nm-124nm
- extremely low frequency (ELF): electromagnetic radiation, frequency 3Hz to 30Hz
- far infrared (FIR): infrared radiation with wavelengths in the 30-450um range
- gamma rays: electromagnetic radiation, wavelength 10 picometers and less
- H-alpha (Ha,Hα, H-α): hydrogen line for electrons settling from n = 3 to n = 2
- infrared (IR): electromagnetic radiation, wavelength .74-300 micrometers
- integral field unit (IFU): instrument to allow a spectrograph to capture data over a 2d field
- K-line: iron X-ray line
- line blanketing: so many bunched spectral lines that they cannot be distinguished
- line broadening: processes causing a spectral line to have width
- Lyman alpha (Ly-α,Lyα): first line in the Lyman series
- Lyman series: hydrogen series from electrons settling from n > 1 to n = 1
- microwave: electromagnetic radiation, frequency 300MHz to 300GHz
- mid infrared (MIR): infrared radiation with wavelengths in the 7.5um-25um range
- near infrared (NIR,near-IR): electromagnetic radiation in the range of 800-2500 nm
- OIR: a spectral "band name" for both visible light and infrared
- oxygen lines: spectral lines specific to oxygen
- P Cygni profile: line profile showing both red and blue shifts
- Paschen series: hydrogen lines for electrons settling from n > 3 to n = 3
- radio: electromagnetic radiation, frequency 3kHz to 300GHz
- spectral line: dark or light line in a spectrum
- spectral power distribution (SPD): function of power versus wavelength or frequency
- subradio: electromagnetic radiation, frequency below 3kHz
- super low frequency (SLF): electromagnetic radiation, frequency 30Hz to 300Hz
- tremendously low frequency (TLF): electromagnetic radiation, frequency below 3Hz
- ultra low frequency (ULF): electromagnetic radiation, frequency 300Hz to 3kHz
- ultra-high-energy gamma rays (UHEGR): energetic gamma rays with more than 100 TeV photon energy
- ultraviolet (UV): electromagnetic radiation, wavelength 10-400 nm
- UVOIR: a spectral "band name" covering UV, visible light, and IR
- very low frequency (VLF): electromagnetic radiation, frequency 3kHz to 30kHz
- very-high-energy gamma rays (VHEGR): energetic gamma rays with 100 GeV to 100 TeV photon energy
- visible light: electromagnetic radiation, wavelength 390-750 nm
- water lines: spectral lines specific to water
- X-ray: electromagnetic radiation, wavelength .01 to 10 nanometers
- XEUV: electromagnetic radiation in the range of .15nm-400nm
- spectrum analysis:
- SPECTRE: an interactive spectrum analysis software package
- spectrum binary: binary star detectable because its spectrum looks like that of two stars
- spectrum synthesis:
- Cloudy: code to model the affect of gas and plasma on spectra
- Spectrum-Roentgen-Gamma:
- eROSITA: future space X-ray telescope
- SPECULOOS: search for Earth-like exoplanets orbiting nearby dim stars
- speed of light (c): fundamental constant measured as the speed at which light travels
- speed of light in a vacuum:
- speed of light (c): fundamental constant measured as the speed at which light travels
- speed of sound:
- sound speed: speed at which compression waves traverse a gas
- SpeedyMCMC:
- Spektr-R: 10m space radio telescope
- Spektr-RG:
- eROSITA: future space X-ray telescope
- SpeX: a medium-resolution infrared spectrograph
- IRTF: Mauna Kea 3-meter infrared telescope
- SPF:
- SPH:
- SPHERE: VLT instrument for imaging exoplanets
- SPHEREx: all-sky spectral survey space-mission plan
- spherical astronomy:
- astrometry: precise measurement of the position and movement of stars
- spherical galaxy:
- galaxy: gravitationally-bound group of stars
- spherical harmonic order:
- spherical harmonics: harmonic functions on the surface of a sphere
- spherical shell:
- SPI:
- INTEGRAL: European gamma ray observatory-satellite
- SPICA: plan for a future space IR telescope
- SPICAM:
- spicule: small temporary jet from Sun's surface
- spin (ms): an angular-momentum quantum number
- spin quantum number:
- Spindle Galaxy (NGC 5866): striking spiral galaxy with very large bulge
- spinning dust:
- spiral:
- spiral arm: long, winding visible structure within a spiral galaxy
- spiral density wave: spiral structure that can form in disks
- spiral galaxies:
- spiral galaxy: flat galaxy with spiraling arms
- spiral nebula:
- Kapteyn universe: early 20th century model of the universe centered on the Milky Way
- spiral structure:
- SPIRE:
- Spirit:
- SPIRITS: Spitzer survey designed to find transients
- Spitzer:
- Spitzer Extended Deep Survey (SEDS): survey of galaxy mass and black holes through life of the universe
- Spitzer Extragalactic Representative Volume Survey (SERVS): infrared survey of some well-studied fields
- Spitzer HETDEX Exploratory Large Area Survey (SHELA): Spitzer-based survey of galaxies
- Spitzer Infrared Intensive Transient Survey:
- SPIRITS: Spitzer survey designed to find transients
- Spitzer Space Telescope (SST): a satellite with infrared telescope
- Spitzer Warm Mission:
- Splashback:
- splashback radius:
- SPOL:
- MMT: 6.5 meter telescope at Mt. Hopkins, Arizona
- spontaneous emission:
- emission: addition of photons to a beam of EMR
- spontaneous symmetry breaking:
- symmetry breaking: loss of symmetry, such as due to loss of stability in a regime change
- Sprite:
- Starshot: plan for mission to fly by Alpha Centauri
- SPS:
- SPS code:
- SPT:
- SPT-CL:
- SPT-SZ:
- SPTpol:
- square degree:
- square degrees:
- Square Kilometre Array (SKA): radio telescope collecting a square kilometer
- square radian:
- square-degree:
- squark:
- SRG:
- eROSITA: future space X-ray telescope
- SRR:
- MDR/SRR: planning step for a NASA mission
- SRT:
- SS:
- SS 433: first microquasar discovered
- SSC:
- SSD:
- SSE:
- ephemeris: information on the position of a celestial body in the sky over time
- SSFR:
- SSI:
- Phoenix: Mars probe launched by NASA in 2007 with lander
- SSP:
- Cassini: explorer spaceship sent to Saturn
- SSS:
- SSSB: solar system body smaller than a dwarf planet
- minor planet: lesser solar system body without comet characteristics
- SSSPM:
- SST:
- St:
- Stokes number (Stk,St): measure of a particle's tendency to flow the flow of a fluid
- Stömgren radius:
- stability radius:
- isolation mass: mass of an oligarch after accreting all nearby planetesimals
- stable isotope:
- isotope: subclass of an element with a specific number of nucleons
- stacking: combining images of the same object
- standard atomic weight:
- element: class of atom based on its number of protons
- standard Big Bang:
- Big Bang: theoretical event when the universe expanded from a point
- standard candle: astronomical object whose brightness can be determined
- standard deviation:
- error bar: feature of a graph to indicate accuracy
- sigma (σ): indication of the confidence level of an experiment
- velocity dispersion (σ): statistical dispersion of velocities of a group of objects
- standard error of the mean:
- error bar: feature of a graph to indicate accuracy
- standard gravitational parameter (μ): a body's mass times the gravitational constant
- standard main sequence:
- standard model: model of elementary particles including quarks
- Lambda-CDM model (ΛCDM,LCDM): Big-Bang cosmological model with a cosmological constant and cold dark matter
- standard model of a flare: description of how solar flares might form
- standard model of particle physics:
- axion (A0): proposed light, electrically neutral elementary particle
- standard model: model of elementary particles including quarks
- supersymmetry: extension to standard model of particle physics
- standard reduction potential:
- standard star:
- star:
- star and planet formation:
- star catalog:
- star catalogue:
- star class:
- star cluster:
- star clusters:
- star count: surveys of stars counting them according to some criteria
- star formation (SF): theorized collapse of gas and dust into stars
- star formation efficiency:
- star formation feedback: mechanisms whereby star formation regulates its own rate
- star formation history (SFH): star formation rate as a function of time
- star formation law:
- star formation main sequence:
- star formation rate (SFR): rate at which material such as gas is turned into stars
- star formation rate density:
- star forming filament:
- filament: linear volume of high molecular gas density within a galaxy
- star forming galaxy:
- star forming region:
- star system: a star and what's gravitationally bound to it
- solar system: the Sun and what's gravitationally bound to it
- star type:
- A-type star (A): type of star with about 2 times the mass of the Sun
- Am star: A-type star with metallic lines
- anomalous X-ray pulsar (AXP): X-ray pulsars with slow rotation and strong magnetic field
- Ap star: peculiar type of A star
- astrometric binary: binary star system detected by observing the movement of a star
- asymptotic giant branch (AGB): a second stage of helium burning in some stars
- B-type star (B): type of star with about 10 times the mass of the Sun
- Be star: early star with Balmer emission lines
- binary neutron star (BNS,NSB): two neutron stars co-orbiting
- binary star: system of two stars co-orbiting
- brown dwarf (BD): star-like object with less mass than a star
- carbon star: star with more carbon than oxygen in its atmosphere
- cataclysmic variable star (CV): star whose magnitude is much larger on occasion
- Cepheid variable: star varying with a constant period
- compact object: dense astronomical body such as white dwarf or denser
- contact binary: binary stars orbiting so close they are touching
- double star: two stars close together in the sky
- double-line spectroscopic binary: spectroscopic binary star where a specific line shows up at two different wavelengths
- eclipsing binary: binary star system detected by variations in magnitude
- F-type star (F): type of star with about 1.5 times the mass of the Sun
- failed binary: like a binary star but one not achieve the mass of a star
- FGK star: a star of class F, G, or K
- field star: star that is not part of a star cluster
- fixed star: star that does not change position in the celestial sphere
- FU Orionis star (FUor): type of variable pre-main-sequence star
- G-type star (G): stars similar to the Sun
- giant star: star larger than main sequence stars
- high-velocity star: star moving noticeably faster than neighbors
- horizontal branch (HB): a second "giant" stage in the evolution of some main sequence stars
- hypergiant: extremely bright stars
- hypermassive neutron star (HMNS): neutron star massive enough to collapse
- hypervelocity star (HVS,HV): star moving very much faster than usual
- K-type star (K): type of star with about 3/4 the mass of the Sun
- L-type star (L): type of star cooler than an M-type star
- low mass star: stars of less than half the solar mass
- M dwarf: small, cool main-sequence star in stellar class M
- M-type star (M): type of star with a temperature in the vicinity of 2500K
- magnetar: neutron star with a strong magnetic field
- main sequence star: star burning hydrogen into helium
- neutron star: stellar remnant consisting entirely of solar masses of neutrons
- O-type star (O): type of star with about 50 times the mass of the Sun
- O5 spectral class (O5): type of star with about 50 times the mass of the Sun
- OB star: a hot star with class O or B
- optical double: two stars that look like one with naked eye
- post main sequence star: star evolved beyond its main sequence phase
- post-common envelope binary (PCEB): binary star system showing unusual stellar evolution
- pre-main-sequence star (PMS): star not yet with a nuclear reaction
- pulsar (PSR): astronomical body whose electromagnetic radiation displays a cycle
- pulsating star: variable star that varies through energy pulses
- radio star: star emitting much radio
- red dwarf: small, cool main-sequence star
- red giant: reddish, giant late stage of stellar evolution
- red-giant branch (RGB): a stage in the evolution of some smaller stars
- RR Lyrae variable: star with periodic variation often in globular clusters
- S-type star: type of star with lines indicating zirconium
- spectral class: classification of spectrums of stars (O, B, A, etc.)
- spectroscopic binary: binary star detected by movement indicated by Doppler shifts in the spectrum
- spectrum binary: binary star detectable because its spectrum looks like that of two stars
- stellar remnant: leftovers from a mainstream star
- subgiant: slightly larger than normal star
- substellar object: star-like object with less mass than a star
- supergiant: very large giant star
- symbiotic binary: giant star transferring mass to a somewhat distant companion
- T-Tauri star (TTS): type of variable pre-main-sequence star
- T-type star (T): type of dwarf with a temperature in the vicinity of 1000K
- Thorne-Żytkow object (TZO,TŻO): giant star with a neutron star at its center
- ultracool dwarf: star or brown dwarf cooler than M7 class
- variable star: star that varies in magnitude
- visual binary: binary star system in which both stars can be seen
- weak-line star: star with faint spectral lines compared to its spectral class
- white dwarf: stellar remnant of mostly electron-degenerate matter
- Wolf-Rayet star: type of star with broad emission bands
- Y-type star (Y): type of dwarf with a temperature less than 700K
- young stellar object (YSO): early stage of a star
- star-formation rate stellar-mass ratio: ratio between a galaxy's stellar mass and its SF rate
- star-forming radio galaxy:
- star-forming region (SFR): areas forming stars or ripe for star formation
- STAR-X: concept for a future X-ray space telescope
- starburst:
- AzTEC-3: very distant starburst galaxy
- HFLS3: very distant starburst galaxy
- M82: nearby starburst galaxy
- NGC 253: spiral galaxy 11 million light-years away
- starburst galaxy: galaxy forming stars at a very high rate
- starburst galaxy: galaxy forming stars at a very high rate
- STARBURST99: software to simulate star-forming galaxies
- StarChip:
- Starshot: plan for mission to fly by Alpha Centauri
- Stardust: space mission to collect comet coma dust
- STARE Telescope:
- starfield:
- asterism: easily recognizable star pattern
- STARFIRE: planned balloon-borne 2.5m telescope and spectroscope
- stars:
- accretion: enlargement of an astronomical body by gravitationally attracting additional mass
- accretion disk: disk around an astronomical body of material that is accreting
- Aitken Double Star Catalogue (ADS): 1932 catalog with multiple star systems and non-orbiting double stars
- APASS: down to 16 magnitude
- asteroseismology: study of stars through analysis of their pulsation
- Astrographic Catalog (AC): historical star catalog of the whole sky to magnitude 11
- Astronomische Gesellschaft Katalog (AGK): 19th/20th century astrometric catalog
- ATLAS Stellar Model: computer model of a stellar photosphere
- atmosphere: gas surrounding astronomical object
- Balmer jump: abrupt change in stellar spectrum at end of Balmer series
- Bayer designation: star designation system dating from 1600s
- Bcool: project studying stellar magnetism
- bipolar outflow: streams of matter from the poles of a protostar
- Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
- Bright Star Catalog (HR,BS,YBS): early 20th century catalog of 9000 stars
- Bruce Proper Motion Survey (BPM): 1941 southern-hemisphere survey catalog of Luyten's
- BT-Settl: model atmosphere of small stars and brown dwarfs
- bulge: denser group of stars within a larger group
- Burnham Double Star Catalogue (BDS,BU): 1906 catalog with multiple star systems and non-orbiting double stars
- calcium-rich gap transient: type of explosive event larger than a nova and smaller than a supernova
- California-Kepler Survey (CKS): followup to Kepler to determine stellar radii
- 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
- CFHTLS: surveys of transients and stars
- Chandrasekhar limit: maximum mass of a white dwarf
- chromosphere: middle layer of the Sun's atmosphere
- chromospheric activity index: measure of magnetic activity of a star's chromosphere
- cold mass accretion (CMA): stellar accretion through an accretion disk
- color-color diagram: means of comparing characteristics of stars
- color-magnitude diagram (CMD): diagram relating color to luminosity
- color-period diagram: means of comparing periods of stars at various wavelengths
- core collapse supernova: supernova resulting from the collapse of the core of a star
- corona: plasma surrounding a star
- coronal mass ejection (CME): mass of plasma ejected from the Sun
- COROT: observatory-satellite to look for transiting exoplanets and stellar oscillations
- CTIO Upper-Scorpius OB Association Survey (UScoCTIO): survey of low-mass stars and brown dwarfs
- debris disk: circumstellar disk of dust and debris around a star
- Dunlop Double Star Catalogue (DUN): 1829 catalog of double stars viewed from Australia
- dwarf nova: flash of a cataclysmic variable star
- Eddington approximation: approximation of a star's internal EMR's divergence from isotropic
- Eddington luminosity: maximum luminosity at which radiation force overcomes gravity
- ejection: forcing or throwing something out
- evolutionary track: H-R diagram track of the life of a star
- field: adjective meaning "in this field of view but unrelated"
- Flamsteed designation: star designation system dating from 1700s
- Frank Ross's Catalog (Ross): high-proper-motion and variable stars catalogued by Frank Ross
- G-dwarf problem: lack of metal-poor G dwarfs in the Milky Way
- Gaia: survey satellite at 400-1000 nanometers
- galaxy main sequence: relation between galaxies' star formation and stellar mass
- 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
- globular cluster (GC): spherical group of stars orbiting a galaxy
- Gould's Belt: ring of stars around the sky
- Guide Star Catalog (GSC,HSTGC): catalog of stars to help aim HST
- gyrochronology: means of estimating stellar age from rotation
- H-R diagram (HRD): diagram relating effective temperature to luminosity
- Hamburg/ESO Survey (HE): 1990s southern hemisphere survey aimed at finding quasars
- Hayashi track: H-R diagram track of evolution of some pre-main-sequence stars
- Heggie-Hills law: hard binary stars generally get harder when encountering a third star
- helium flash: helium ignition in a star
- helium runaway shell: helium ignition in a shell in AGB giants
- Henry Draper Catalog (HD): early 20th century spectroscopic catalog of stars
- Herschel Double Star Catalog (H): series of early double star catalogs
- initial mass function (IMF): function describing initial mass of stars
- instability strip: region of H-R diagram where stars are unstable
- interstellar magnetic field (ISMF): galactic magnetic field between that of stars
- isothermal core: core region of a body of all the same temperature
- kilonova: explosive event larger than a nova and smaller than a supernova
- 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
- luminosity class: classification of size/luminosity of stars
- luminosity function (LF): function giving number of stars or galaxies at different luminosities
- 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
- mass fraction: measure of a constituent of a star, cloud, etc.
- mass loss: a star's reduction in mass
- mass-luminosity relation: model relating stellar mass and luminosity
- mass-radius relation: model relating stellar mass and radius
- mass-to-light ratio (M/L,ϒ): measure of a population of stars or region
- Max Wolf's catalog of stars with proper motion: early 20th century catalog of 1500 stars
- mean molecular weight (μ): measurement of a gas usual for approximating in gas models
- microquasar: stellar-sized black hole with quasar-like activity
- moving-cluster method: method of measuring distance to a nearby star cluster
- multiplicity fraction: fraction of star systems that are multiple-star systems
- MUSCLES: HST UV survey of some M Dwarfs that host exoplanets
- New Catalogue of Suspected Variable Stars (NSV): catalog from latter half of 20th century catalog
- NOMAD: astrometric star catalog
- nova: white dwarf explosion
- OB association: stellar association with O or B class stars
- Oort constants: two constants characterizing local Milky-Way motion
- open cluster: group of stars within a galaxy apparently formed by a single cloud
- partial ionization zone: portion of some stars where gas is partially ionized
- PHOENIX stellar model: computer model of a stellar photosphere
- photosphere: layer of start from which light propagates
- Pico dos Dias Survey (PDS): survey aimed to find T-Tauri stars
- plane-parallel atmosphere: simplified atmosphere model ignoring its curvature around the body
- planetary nebula (PN, PNe): gas shell ejected by a red giant
- planetary system: all the planets orbiting a star
- PPM Star Catalogue: 1991 astrometric catalog with proper motions
- protoplanetary nebula (PPN): AGB phase before planetary nebula
- protostar: contracted mass of gas that will become a star
- quadratic field strength: a measure of a star's varying magnetic field
- quasar (QSO): distant, bright object that appears something like a star
- RECONS: consortium for research on stars near the Sun
- Rosseland mean opacity: a useful weighted average of opacities at all the wavelengths
- SAO Star Catalog: 1960s catalog
- Schönberg-Chandrasekhar limit: maximum stellar isothermal helium core mass
- Schuster-Schwarzschild model: approximation of a star's internal EMR's divergence from isotropic
- seismic waves: waves broadcast from earthquakes
- snow line: distance from protostar cool enough for water to condense
- spectral class: classification of spectrums of stars (O, B, A, etc.)
- star count: surveys of stars counting them according to some criteria
- star formation (SF): theorized collapse of gas and dust into stars
- star system: a star and what's gravitationally bound to it
- STARBURST99: software to simulate star-forming galaxies
- stellar age determination: methods of estimating a star's age
- stellar association: like a large open cluster but even less tightly bound
- stellar atmosphere: photosphere and above
- stellar birth rate function: function describing the birth rate of stars by mass
- stellar cluster: group of stars apparently formed by a single cloud
- stellar core: the middle of a star
- stellar designation: identifiers for stars
- stellar distance determination: methods by which the distance to a star is determined
- stellar dynamics: stars' gravitational interaction
- stellar encounter: stars passing close to each other
- stellar evolution: the pattern of a star's changing structure over its life
- stellar flare: sudden brightening of a star
- stellar luminosity determination: methods by which the luminosity of a star is determined
- stellar mass determination: methods by which the mass of a star is determined
- stellar model atmosphere: simulation of the star's production of emitted EMR
- stellar parameter determination: methods by which the parameters of stars are determined
- stellar population synthesis (SPS): using spectral characteristics of galaxies to characterize their stellar populations
- stellar population synthesis code: software to perform stellar population synthesis
- stellar radius determination: methods by which the radius of a star is determined
- stellar rotation: the angular motion of a star around its axis
- stellar structure: the presumed internal structure of stars
- stellar temperature determination: methods by which the temperature of a star is determined
- stellar wind: gas or plasma emanating from a star
- Struve Catalogs: two catalogs of double stars
- sunspot: temporary darker region of the Sun's surface
- SuperCOSMOS Sky Survey (SSS): survey of stars and galaxies from legacy plates
- superluminous supernova (SLSN): stellar explosion larger than a supernova
- supernova (SN): stellar explosion larger than a nova
- surface abundance: quantity such as mass per surface area
- surface gravity: force felt at the surface of a body
- surface temperature: temperature of the surface of a star or planet
- synthetic spectrum: simulated spectrum, e.g., of a type of star
- Taurus-Auriga Complex: nearby star-forming region
- thermal pulse: pulse in an AGB star due to helium fusion in a shell
- tidal capture: bodies entering orbit through dissipation of energy by tides
- Tolman-Oppenheimer-Volkoff limit (TOV,LOV): maximum mass of a neutron star
- turn-off point (TO): point in H-R diagram of a cluster where stars turn red
- Two Micron All-sky Survey (2MASS): near-infrared survey of both hemispheres
- two-stream approximation: approximation of a star's internal EMR's divergence from isotropic
- Type Ia supernova: type of supernova for which distance can be determined
- variable star designation: Bayer system variant for variable stars
- velocity-metallicity relation: higher stellar velocity correlates with lower metallicity
- Vogt-Russell theorem: proposition that a star's structure depends on its mass and makeup
- Washington Double Star Catalog (WDS): modern database of double stars
- Wilson-Bappu effect: a relation between a star's spectral line and luminosity
- WINGS: all-sky survey investigating known galaxy clusters
- zero-age main sequence (ZAMS): describes stars that just began hydrogen fusion
- StarScan machine:
- starshade: spacecraft to block light from a specific body
- Starshot: plan for mission to fly by Alpha Centauri
- starspot:
- StarTrack: stellar population synthesis code
- state of excitation: energy level of something above the minimum
- state of ionization: difference in an ion's electron count versus proton count
- static limit:
- black hole (BH): region of such high mass that light cannot escape
- static surface:
- black hole (BH): region of such high mass that light cannot escape
- statics:
- statistical dispersion:
- statistical equilibrium:
- statistical isotropy:
- statistical mechanics: mechanical behavior based upon probability
- statistical physics:
- statistical weight:
- statistics:
- stau:
- steady-state universe:
- Big Bang: theoretical event when the universe expanded from a point
- steam atmosphere:
- steam phase:
- steam planet:
- Stefan's constant:
- Stefan-Boltzmann constant (σ): relates radiation power to temperature and surface area
- Stefan-Boltzmann equation:
- Stefan-Boltzmann law:
- stellar age:
- stellar age determination: methods of estimating a star's age
- stellar association: like a large open cluster but even less tightly bound
- stellar atmosphere: photosphere and above
- stellar birth rate function: function describing the birth rate of stars by mass
- stellar black hole:
- black hole (BH): region of such high mass that light cannot escape
- stellar evolution: the pattern of a star's changing structure over its life
- stellar class:
- stellar classification:
- stellar cluster: group of stars apparently formed by a single cloud
- field star: star that is not part of a star cluster
- stellar core: the middle of a star
- stellar designation: identifiers for stars
- stellar distance:
- stellar distance determination: methods by which the distance to a star is determined
- stellar dynamics: stars' gravitational interaction
- stellar encounter: stars passing close to each other
- stellar envelope:
- stellar evolution: the pattern of a star's changing structure over its life
- stellar evolution model:
- stellar feedback:
- stellar flare: sudden brightening of a star
- stellar kinematics:
- stellar luminosity:
- stellar luminosity determination: methods by which the luminosity of a star is determined
- stellar magnetic field:
- stellar mass:
- stellar mass black hole:
- stellar mass determination: methods by which the mass of a star is determined
- stellar mass loss:
- stellar metallicity:
- stellar model:
- stellar model atmosphere: simulation of the star's production of emitted EMR
- stellar nucleosynthesis:
- stellar nucleus: group of many stars at the center of a galaxy
- stellar nursery:
- stellar parallax:
- parallax: angle due to different lines of sight
- stellar parameter determination: methods by which the parameters of stars are determined
- stellar population: grouping of stars according to metallicity
- stellar population synthesis (SPS): using spectral characteristics of galaxies to characterize their stellar populations
- stellar population synthesis code: software to perform stellar population synthesis
- stellar population synthesis model:
- stellar pulsation:
- stellar radio source:
- stellar radius:
- stellar radius determination: methods by which the radius of a star is determined
- stellar remnant: leftovers from a mainstream star
- stellar remnant black hole:
- black hole (BH): region of such high mass that light cannot escape
- stellar rotation: the angular motion of a star around its axis
- stellar seismology:
- stellar structure: the presumed internal structure of stars
- stellar structure equations:
- stellar structure model:
- stellar system:
- solar system: the Sun and what's gravitationally bound to it
- star system: a star and what's gravitationally bound to it
- stellar temperature:
- stellar temperature determination: methods by which the temperature of a star is determined
- stellar type:
- stellar wind: gas or plasma emanating from a star
- stellar-mass star-formation rate ratio:
- stencil: pattern of input to numerical solutions at a point
- steradian:
- STEREO: two-satellite system to observe the Sun
- sterile neutrino:
- neutrino (ν): light, electrically neutral elementary particle
- Sternberg Astronomical Institute:
- Steward Observatory 0.9-meter Spacewatch telescope:
- STF:
- STFC:
- stimulated emission:
- emission: addition of photons to a beam of EMR
- STIS:
- Stk:
- Stokes number (Stk,St): measure of a particle's tendency to flow the flow of a fluid
- stochastic background:
- Stokes number (Stk,St): measure of a particle's tendency to flow the flow of a fluid
- Stokes parameters: way to describe polarization state
- stop:
- Lyot stop: optical element to block unwanted light within instruments
- Strömgren photometric system: four-color photometric system devised in 1950s
- Strömgren sphere: sphere of ionized hydrogen around an OB star
- strange quark:
- Strasbourg-ESO Catalog of Galactic Planetary Nebulae (PNG): 1992 catalog of 1820 objects
- stratigraphy: study of rock layering
- stratopause:
- stratosphere:
- Stratospheric Observatory for Infrared Astronomy:
- SOFIA: aircraft-based infrared observatory
- stray light: unintended light reaching a telescope's sensors
- stray light mitigation:
- stray light: unintended light reaching a telescope's sensors
- Strehl ratio: measure of optical aberration
- wavefront error (WFE): measure of a telescope's distortion of incoming waves
- strewn field: region with fragments of a meteor impact
- strewn-field:
- strewnfield:
- striae: parallel ridges
- string theory:
- strong cosmic censorship:
- strong CP problem:
- axion (A0): proposed light, electrically neutral elementary particle
- strong encounter:
- strong force: force that holds quarks and nuclei together
- strong gravitational encounter:
- strong gravitational interaction:
- strong gravitational lensing:
- weak lensing: slight lensing detected in random patterns of distant objects
- strong interaction:
- N-body problem: calculating the paths of gravitationally-interacting celestial objects
- strong force: force that holds quarks and nuclei together
- strong lensing:
- weak lensing: slight lensing detected in random patterns of distant objects
- Strong Radio Source Surveys:
- Strong Source Surveys: series of 1970s/1980s 5GHz surveys
- strong stellar encounter:
- strong-field gravity: gravity much stronger than in the solar system such as near a black hole
- strong-field gravity physics:
- strontium:
- Am star: A-type star with metallic lines
- Ap star: peculiar type of A star
- Struve:
- Struve 1341 B b:
- Struve Catalogs: two catalogs of double stars
- STScI:
- STT:
- STTA:
- Styx:
- Pluto: dwarf planet formerly listed as one of the nine planets
- sub Neptune:
- super-Earth: exoplanet more massive than Earth but substantially less than Neptune
- sub-brown dwarf:
- Subaru:
- Subaru Deep Field (SDF): survey of a small region of the sky using the Subaru telescope
- Subaru Telescope: 8.2 meter telescope in Hawaii
- Subaru XMM Deep Survey:
- Subaru XMM-Newton Deep Field:
- Subaru XMM-Newton Deep Survey (SXDS): survey using the Subaru telescope and XMM-Newton
- subgiant: slightly larger than normal star
- subgrid physics:
- subgrid-scale physics: shortcuts handling physics on a smaller scale than a simulation's grid
- sublimation: single material phase transition from solid to gas
- submillimeter:
- Submillimeter Array (SMA): radio interferometer in Hawaii
- submillimeter astronomy: astronomy observation and analysis of borderline infrared EMR
- far infrared (FIR): infrared radiation with wavelengths in the 30-450um range
- submillimeter galaxy (SMG): galaxy that produces significant submillimeter radiation
- submillimeter galaxy designator: designation system of submillimeter galaxies
- Submillimeter Telescope (SMT,HHSMT): 10 meter far-infrared telescope
- submillimeter-selected galaxy:
- submillimetre astronomy:
- Submillimetre Common-user Bolometer Array:
- SCUBA: submillimeter instrument on James Clark Maxwell Telescope
- submoon:
- subradio: electromagnetic radiation, frequency below 3kHz
- subsatellite: object orbiting a moon
- substar:
- Substellar and Planetary Atmospheric Radiation and Circulation:
- MITgcm: well-known general circulation model
- substellar object: star-like object with less mass than a star
- SUDA:
- sugar:
- Lego principle: principle that life is associated with a skew in molecule abundances
- sulci:
- Enceladus: Saturn moon considered possible carrier of life
- sulfide:
- geochemistry: the chemistry of the Earth, planets, and moons
- sulfur (S): metal, S, atomic number 16
- SUMER:
- summer solstice:
- solstice: moment when Sun reaches its northern- or southern-most position
- Sun: star at center of solar system
- sunspot: temporary darker region of the Sun's surface
- 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
- super giants:
- super Jupiters:
- super low frequency (SLF): electromagnetic radiation, frequency 30Hz to 300Hz
- super Neptune:
- super rotation:
- super-Earth: exoplanet more massive than Earth but substantially less than Neptune
- super-Eddington accretion:
- accretion: enlargement of an astronomical body by gravitationally attracting additional mass
- Eddington luminosity: maximum luminosity at which radiation force overcomes gravity
- super-Eddington luminosity:
- super-puff:
- super-Earth: exoplanet more massive than Earth but substantially less than Neptune
- superbubble:
- SuperCam:
- supercluster: cluster of galaxy clusters
- supercluster complex:
- superconducting fluid:
- neutron star: stellar remnant consisting entirely of solar masses of neutrons
- supercooled state:
- supercooling: cooling water below freezing point without it freezing
- supercooling: cooling water below freezing point without it freezing
- SuperCOSMOS:
- SuperCOSMOS Sky Survey (SSS): survey of stars and galaxies from legacy plates
- SuperCOSMOS Sky Surveys:
- superearth:
- super-Earth: exoplanet more massive than Earth but substantially less than Neptune
- superflare:
- superfluid:
- supergalactic coordinate system: celestial coordinate system system based upon the supergalactic plane
- supergalactic latitude:
- supergalactic longitude:
- supergalactic plane:
- supergiant: very large giant star
- supergiant star:
- supergranulation:
- Sun: star at center of solar system
- superionic ice: odd state of water at high temperature and pressure
- superionic water:
- superionic water ice:
- superior planet:
- superluminal motion: faster-than-light movement
- superluminous SN:
- superluminous supernova (SLSN): stellar explosion larger than a supernova
- supermassive binary black hole:
- supermassive black hole (SMBH): black hole with a mass of millions to billions of solar masses
- supermassive black hole binary:
- binary SMBH (BSMBH,SMBBH,SMBHB): co-orbiting supermassive black holes
- supermassive black holes:
- supermassive neutron star:
- supernova (SN): stellar explosion larger than a nova
- Cassiopeia A: supernova remnant visible for 300 years
- SN 1987A (1987A): supernova in February 1987 rare for being visible by the naked eye
- SN 2014J: type Ia supernova in Messier 82, the Cigar Galaxy
- Supernova Acceleration Probe:
- WFIRST: proposed space observatory
- Supernova Cosmology Project (SCP): used supernova data to determine a history of the universe's expansion
- Supernova Factory Galaxy:
- NGC 2770: spiral galaxy 88 million light-years away
- Supernova Legacy Survey (SNLS): detect and monitor supernovae to measure the effects of dark energy
- supernova nucleosynthesis:
- supernova remnant (SNR): nebula of debris resulting from a supernova
- supernova (SN): stellar explosion larger than a nova
- supernovae:
- superparticle:
- superposition:
- linear theory: theory of operators satisfying the property of superposition
- superradiance: Exotic quantum-mechanics light-amplification phenomenon
- superrotating jet:
- superrotating wind: wind traveling in the same direction as the planet is rotating
- supershell:
- supersonic parachute:
- drogue chute: parachute to slow something moving at high speed
- supersymmetry: extension to standard model of particle physics
- neutralino: proposed type of particle that might include wimps
- supervoid:
- void: empty spaces between large scale structures
- SuperWASP (SWASP): broad Earth-based search for transiting planets
- SuperWASP-North:
- SuperWASP (SWASP): broad Earth-based search for transiting planets
- superwind:
- suprathermal: having more energy than would be created by thermal excitation
- Suprime-Cam:
- surface:
- surface abundance: quantity such as mass per surface area
- surface brightness: brightness per unit area of a surface
- surface brightness fluctuation (SBF): apparent indication of an elliptical galaxy's distance
- surface brightness fluctuations method:
- surface density (Σ): quantity such as mass per surface area
- surface error:
- wavefront error (WFE): measure of a telescope's distortion of incoming waves
- surface gravity: force felt at the surface of a body
- surface reaction: such as reactions between gas and adjacent liquid
- surface temperature: temperature of the surface of a star or planet
- survey:
- 1 Jansky Empty Field Survey (1 Jy): survey to find optical identifications for weak radio sources
- 2dF Galaxy Redshift Survey (2dFGRS): imaging survey of 300,000 objects
- 2dF-SDSS LRG and QSO survey (2SLAQ): spectroscopic survey of distant galaxies
- 3D-HST: near-infrared survey of 100,000 galaxies by HST
- 87GB Catalog of Radio Sources (87GB): 1980s Green Bank radio survey
- AEGIS: survey study of distant galaxies
- AIM-CO: survey of CO from star forming epoch
- ALFALFA: HI survey of many galaxies
- All Sky Automated Survey (ASAS): Polish survey of 20,000 objects brighter than 14 magnitude
- All Sky Automated Survey for SuperNovae (ASAS-SN,ASASSN): survey of both hemispheres for supernovae
- ALMA-PILS Survey: millimeter survey of a protostar
- APASS: down to 16 magnitude
- APM Galaxy Survey (APMUKS): 1990s survey of galaxies in southern sky
- Arecibo Occultation Survey (AO): 1960s radio survey using occultations by the Moon
- ASPECS: millimeter survey of HUDF
- Astrographic Catalog (AC): historical star catalog of the whole sky to magnitude 11
- astronomical survey: project to collect uniform astronomical data across the sky
- Atlas 3d: survey of local galaxies
- Australia Telescope Large Area Survey (ATLAS): radio survey of two survey fields
- Badgerys Creek Interferometer 101MHz Survey (Mills): early 1950s survey of southern-hemisphere radio sources
- Baryon Oscillation Spectroscopic Survey (BOSS): survey of spatial distribution of luminous red galaxies and quasars
- BICEP2: survey to measure the polarization of the CMB
- BigBOSS: BOSS survey follow-on
- Bologna Survey of Radio Sources: 1970s-1980s radio survey
- Bruce Proper Motion Survey (BPM): 1941 southern-hemisphere survey catalog of Luyten's
- C-BASS: 6 cm survey of the entire sky
- Calán/Tololo Survey: late 1980s to early 1990s search to redshift .1
- CALIFA: spectroscopic map of 600 galaxies
- California-Kepler Survey (CKS): followup to Kepler to determine stellar radii
- Canada-France High-z Quasar Survey (CFHQS): 2000s distant quasar survey
- CARMA EDGE: CO survey of galaxies
- Catalina Sky Survey (CSS): survey of near-Earth objects
- CFBDS: survey in search of brown dwarfs
- CFHTLS: surveys of transients and stars
- 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
- COLD GASS: survey of CO in nearby large galaxies
- COMPLETE Survey: survey of star forming regions
- COPSS: survey of CO from star forming epoch
- 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 Lens All-sky Survey (CLASS): radio survey aimed at gravitational lenses
- CRATES: catalog of 8.4GHz data on radio sources
- 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
- DASCH: project to digitize Harvard astronomy plates
- DECaLS: survey imaging part of SDSS footprint with DECam
- DEEP2: redshift survey of 60,000 galaxies
- DeGaS-MC: GBT survey of potential star formation regions in the Magellanic Clouds
- DENIS: 1990s southern sky survey of two near-infrared bands
- DEVILS: visible-light spectrographic survey of 56k distant galaxies
- Digitized Sky Survey (DSS): digitization of Palomar and UK Schmidt plates
- 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
- Dwingeloo Obscured Galaxy Survey (DOGS): radio survey of ZOA for 21cm lines indicating galaxies
- EMPIRE Survey: survey of gas in M51a to follow up PAWS
- EROS: search for MACHOs
- eROSITA: future space X-ray telescope
- ESO/Uppsala Survey of the ESO (B) Atlas: 1970s southern all-sky survey
- ESSENCE: survey using supernova data to study dark energy
- Extended Chandra Deep Field-South Survey (ECDFS): 1100 square arcminute X-ray survey
- Faint Infrared Grism Survey (FIGS): survey to identify redshift of distant galaxies
- FIRST: 1990s radio survey
- Fourth Cambridge Catalog of Radio Sources (4C): 1960s catalog of northern hemisphere 178MHz sources
- Gaia: survey satellite at 400-1000 nanometers
- Galactic All-sky Survey (GASS): HI survey of the Milky Way
- GALAH: survey of Milky Way with an emphasis on old structures
- Galaxy Zoo 2 (GZ2): crowd-sourced classification of hundreds of thousands of galaxies
- GALEX Arecibo SDSS Survey (GASS): HI survey of many galaxies
- GAMA: galaxy spectroscopy survey to roughly 1 Mpc
- GMAN: collaboration to alert on microlensing transients
- GOODS: survey combining data from different sources on very distant objects
- GOODS NICMOS Survey (GNS): survey with HST NICMOS instrument of galaxies in GOODS fields
- Gould's Belt Distances Survey (GOBELINS): survey of parallax distances to Gould's Belt YSOs
- Green Bank 6-cm Radio Source Catalog (GB6): catalog of from 1980s northern-hemisphere radio survey
- Hamburg Schmidt Survey (HS): photographic plates from the Hamburg Schmidt Camera
- Hamburg/ESO Survey (HE): 1990s southern hemisphere survey aimed at finding quasars
- HATNet: distributed array of telescopes to search for transients
- Hawaii K-band Galaxy Survey: near-infrared survey of a selection of fields
- HBK: study of M31 globular clusters
- Herschel Orion Protostar Survey (HOPS): survey of SEDs of YSOs in Orion
- Herschel Redshift Survey (HeRS): 70 square-degree survey of galaxies redshifted 1.8 to 3.5
- Hewitt & Burbidge Catalog (HB87): optical catalog of quasi-stellar objects
- HIPASS: HI survey carried out 1997 to 2002
- Hubble Deep Field (HDF,HDF-N): highly-detailed image of a small region of the sky taken with HST
- Hubble Deep Field South (HDF-S): small region of the southern sky explored with HST
- Hubble Ultra-Deep Field (HUDF): extremely detailed HST image of a small region of space
- KELT: pair of telescopes searching for transients
- Kiso Survey of Ultraviolet Excess Galaxies (KUG): 1980 Japanese survey
- KMOS3D: survey of galaxies before to after peak star formation
- LABOCA Extended Deep Field South Submillimetre Survey (LESS): submillimeter survey of a well-studied piece of sky
- Large Bright QSO Survey (LBQS): 1980s quasar survey
- Lick Observatory Calcium Line Survey (LkCl): 1980s survey of T-Tauri stars in the Taurus-Auriga Complex
- Lick Observatory Supernova Search (LOSS): search for supernovae for cosmological study
- LINEAR: survey of near-Earth objects
- LONEOS: survey of near-Earth objects
- Lupus Transit Survey: survey for hot Jupiters in a region of constellation Lupus
- MACHO Project: survey searching out microlensing that could indicate a MACHO
- Magellanic Clouds Photometric Survey (MCPS): UBVI survey of the Magellanic Clouds
- Markarian galaxy (Mkn): list of galaxies with excess ultraviolet light
- MASCARA: distributed array of telescopes to search for exoplanets
- Massive Cluster Survey (MACS): survey of distant clusters evident in ROSAT X-ray data
- MEarth Project (MEarth): automated observatories monitoring nearby red dwarfs for transits
- MIGHTEE: radio survey of four established deep fields
- Millimeter-wave Intensity Mapping Experiment (mmIME): project to map CO an [CII]
- MOA: search for microlensing
- MOJAVE: program to monitor AGN jet radio brightness and polarization
- Molecular Deep Field: survey of molecular lines in Hubble Deep Field
- MUSCLES: HST UV survey of some M Dwarfs that host exoplanets
- Nearby Supernova Factory (NSNF,SNfactory): survey that scanned transient data for supernovae
- NGTS: survey of transits from Chile
- NRAO Catalog (NRAO): 1960s followup to Cambridge radio surveys
- NRAO VLA Sky Survey (NVSS): 1990s microwave survey of 82% of the sky
- OGLE: survey searching for microlensing transients
- Ohio Radio Survey: 1960s radio survey by Ohio State University
- Outer Solar System Origins Survey (OSSOS): survey searching for trans-Neptune objects
- PALMS: survey to find exoplanets for direct imaging
- Palomar Four-filter Survey (PC): Hale telescope survey aimed at discovering high-redshift quasars
- Palomar Observatory Sky Survey (POSS): 1950s photographic plates from Palomar 48 inch telescope
- Palomar Transient Factory (PTF): survey designed to find transients
- Palomar-Green Survey (PG): list of quasars with excess ultraviolet light
- Pan-STARRS: set of survey telescopes
- PanCET: HST UV/optical/NIR survey of selected exoplanets
- PAndAS: survey of M31 and M33
- Parkes Catalog (PKS): catalog of from 1960s-1990 of radio sources in southern hemisphere
- Parkes HI Zone of Avoidance Survey (HIZOA): radio survey to identify galaxies hidden by the zone of avoidance
- Parkes Pulsar Timing Array (PPTA): group of pulsars timed by Parkes Observatory
- Parkes-MIT-NRAO Surveys (PMN): 1990 southern-hemisphere radio surveys
- PAWS: survey of GMCs in M51a
- PEP: survey aimed at early star formation
- PESSTO: survey for transients carried out on the NTT
- PHIBSS: survey of CO in distant galaxies
- Pi of the Sky: survey aimed at finding gamma-ray-burst visual counterparts
- Pico dos Dias Survey (PDS): survey aimed to find T-Tauri stars
- POINT-AGAPE: survey of M31 for microlensing
- POLARBEAR: instrument to map CMB polarization
- Pre-OmegaTranS (POTS): transit search using MPG/ESO Telescope
- Probing Lensing Anomalies Network (PLANET): survey that recorded microlensing event lightcurves
- Qatar Exoplanet Survey (QES): photometric survey in search of transients
- QUIJOTE: survey to measure the polarization of the CMB
- Radio Galaxy Zoo (RGZ): crowd-sourced classification of radio galaxies
- Rosat Bright Survey (RBS): list of bright X-ray sources from ROSAT observations
- Rosat Hard Survey (RHS): list of hard X-ray sources from ROSAT observations
- SAGE: survey of gas and dust in the Magellanic Clouds
- Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS): transit search using HST time
- Second Byurakan Survey (SBS): 1970s-1990s survey of galaxies and quasars
- SINS: near-infrared study of distant luminous galaxies
- SKHB: survey of globular clusters in M31
- SkyMapper Southern Survey (SMSS): digital survey of the southern hemisphere sky
- Sloan Digital Sky Survey (SDSS): imaging survey of 500,000,000 objects in 35% of sky
- SPACEWATCH: survey to study minor planets
- SPECULOOS: search for Earth-like exoplanets orbiting nearby dim stars
- SPHEREx: all-sky spectral survey space-mission plan
- SPIRITS: Spitzer survey designed to find transients
- Spitzer Extended Deep Survey (SEDS): survey of galaxy mass and black holes through life of the universe
- Spitzer Extragalactic Representative Volume Survey (SERVS): infrared survey of some well-studied fields
- Spitzer HETDEX Exploratory Large Area Survey (SHELA): Spitzer-based survey of galaxies
- Strong Source Surveys: series of 1970s/1980s 5GHz surveys
- Subaru Deep Field (SDF): survey of a small region of the sky using the Subaru telescope
- Subaru XMM-Newton Deep Survey (SXDS): survey using the Subaru telescope and XMM-Newton
- SuperCOSMOS Sky Survey (SSS): survey of stars and galaxies from legacy plates
- 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
- SuperWASP (SWASP): broad Earth-based search for transiting planets
- Swope Supernova Survey (SSS): survey of low-redshift Type Ia SN lightcurves
- Texas Survey of Radio Sources at 365 MHz (TXS): 1970s/1970s radio survey made with the Texas Interferometer
- The H2O Southern Galactic Plane Survey (HOPS): survey of molecular clouds in the galactic plane
- Tomographic Ionized-carbon Mapping Experiment (TIME): proposed instrument to map the [CII] line
- Tonantzintla Surveys (Ton): surveys providing early images of quasars and Seyfert galaxies
- Trans-Atlantic Exoplanet Survey (TrES): exoplanet-search survey using three telescopes
- Two Micron All-sky Survey (2MASS): near-infrared survey of both hemispheres
- UK Schmidt Survey: photographic survey of the southern hemisphere sky
- UKIDSS: five-part infrared survey using UKIRT
- Ultimate Spitzer Phase Curve Survey (USPCS): investigation of exoplanet atmospheres
- Ultraviolet Hubble Ultra-deep Field (UVUDF): ultraviolet data covering the Hubble Ultra Deep Field region of the sky
- UltraVISTA: near infrared survey using VISTA telescope
- VIRMOS-VLT Deep Survey (VVDS): spectroscopic survey of 100,000 high-redshift galaxies
- WASP: multi-university initiative to locate transiting planets
- Westerhout Radio Survey (W): 1950s radio survey of the galactic plane
- WFCAM Transit Survey (WTS): 2000s survey for exoplanet transits using UKIRT
- WiggleZ: survey aimed at mapping dark energy
- WINGS: all-sky survey investigating known galaxy clusters
- XO Project: initiative to search for transiting planets
- Survey and Time-domain Astrophysical Research Explorer:
- STAR-X: concept for a future X-ray space telescope
- survey depth: indication of how far a survey reaches
- survey field: portion of the celestial sphere where a survey's observations aim
- survey region:
- survey field: portion of the celestial sphere where a survey's observations aim
- survey-based designator: astronomical object designators based on name of survey
- Surveying the Agents of Galaxy Evolution:
- SAGE: survey of gas and dust in the Magellanic Clouds
- surveys:
- astronomical catalog: lists of observed astronomical bodies and their characteristics
- astronomical survey: project to collect uniform astronomical data across the sky
- blind survey: survey conducted independently of prior information
- completeness: measure of how many of a survey's objects of a certain magnitude have been detected
- deep field (DF): survey field subject to lengthy observation to identify distant galaxies
- deep survey: survey using lengthy observation to identify distant galaxies
- Fsky (fsky): fraction of the sky, e.g., what a survey covers
- Hα survey: survey looking for the Hα line, typically to find star formation
- MAST: archive of data from surveys and missions
- QUEST: sixteen square-degree survey camera
- redshift survey: survey of the universe aiming at three dimensions
- scan speed: the speed at which the telescope changes angle on the sky while observing
- slew survey: survey conducted by imaging during a telescope's repointings
- star count: surveys of stars counting them according to some criteria
- survey depth: indication of how far a survey reaches
- survey field: portion of the celestial sphere where a survey's observations aim
- survey-based designator: astronomical object designators based on name of survey
- Sutherland:
- Sutherland Station:
- MeerLICHT: South African telescope to coordinate with MeerKAT
- Suzaku: space X-ray telescope
- SW effect:
- SWAN:
- SWAP:
- SWASP:
- SuperWASP (SWASP): broad Earth-based search for transiting planets
- SWAVES:
- STEREO: two-satellite system to observe the Sun
- SWCam:
- CCAT: 25 meter submillimeter telescope plan for Chile
- SWE:
- sweep signal:
- chirp: burst of signal rising or falling in frequency
- SWEEPS:
- SWeffect:
- SWEPAM:
- SWI:
- JUICE: mission to Jupiter in development
- SWICS:
- Swift: satellite for studying gamma-ray bursts
- Swift Gamma-Ray Burst Mission:
- Swift: satellite for studying gamma-ray bursts
- SWIMS:
- swing by:
- Mars: well-explored planet in the solar system
- SWIRC:
- MMT: 6.5 meter telescope at Mt. Hopkins, Arizona
- SWIRE:
- Swiss T70 Telescope:
- TRAPPIST: ground-based automatic transiting planet finding telescope
- Swope Supernova Survey (SSS): survey of low-redshift Type Ia SN lightcurves
- Swope Telescope:
- Swordy plot:
- cosmic rays (CR): very-high-energy particles from beyond the solar system
- SWP:
- SWR:
- SWS:
- SXDF:
- SXDS:
- SXI:
- ASTRO-H: Japanese space X-ray telescope
- SXS:
- ASTRO-H: Japanese space X-ray telescope
- SXT:
- ASTRO-H: Japanese space X-ray telescope
- Yohkoh: 1990s Japanese solar observatory spacecraft
- symbiotic binary: giant star transferring mass to a somewhat distant companion
- symbiotic star:
- symbol:
- Z+: symbol for ion or ion charge
- symmetry breaking: loss of symmetry, such as due to loss of stability in a regime change
- synchronous orbit: orbit with angular velocity matching the rotation of the orbited body
- synchronous rotation:
- synchrotron:
- synchrotron luminosity:
- synchrotron radiation: radiation emitted when high-speed charged particles are accelerated
- synchrotron self-absorption:
- synchrotron self-Compton (SSC): charged particle cloud scattering its own synchrotron-produced photons
- synchrotron self-scattering:
- synestia model:
- synodic period: period until a planet returns to the same position relative to the Sun
- orbital period: length of time for an orbiting object to complete one cycle
- synoptic: general, covering everything
- synthesis imaging:
- Synthesis Telescope:
- synthetic field method (SFM): method of testing galaxy opacity
- synthetic photometry: deriving photometry-style data from spectroscopy
- synthetic spectrum: simulated spectrum, e.g., of a type of star
- System Requirements Review:
- MDR/SRR: planning step for a NASA mission
- systematic error:
- sigma (σ): indication of the confidence level of an experiment
- systemic redshift:
- systemic velocity: average velocity of grouped objects, such as a galaxy
- syzygy:
- opposition: positioning of two astronomical objects 180 degrees apart in the sky
- SZ:
- SZ Array:
- SZ effect:
- SZ/CMB-Pol:
- CCAT-prime (CCAT-p): planned 6 meter submillimeter telescope in Chile
- SZA:
- SZE:
index