Term Index (B)
Astrophysical terms and names of things beginning with the letter B.
B0
B1
B2
B3
B4
BA
BB
BC
BD
BE
BF
BG
BH
BI
BJ
BK
BL
BM
BN
BO
BP
BR
BS
BT
BU
BV
BW
BY
BZ
- B: photometric filter for blue light
- B (B-type star): star with spectral characteristics of around 10000-30000 K
- B (Barnard Catalog): 1919 catalog of dark nebulae
- B (magnetic flux density): vector field describing magnetism in relation to the Lorentz force
- B: see J designator
- B: see double star designation
- B: see epoch B1950.0
- B: see rare designator prefixes
- B Cassiopeiae (SN 1572): Type Ia supernova noted in 1572 by Tycho Brahe
- B field (magnetic flux density): vector field describing magnetism in relation to the Lorentz force
- B-band: see Hubble Ultra-Deep Field
- B-BOP: see SPICA
- B-class: see B-type star
- B-class star (B-type star): star with spectral characteristics of around 10000-30000 K
- B-E statistics (Bose-Einstein statistics): possible distribution of particles not bound by Pauli exclusion
- B-mode: see polarization modes
- B-type star: star with spectral characteristics of around 10000-30000 K
- B-type subdwarf: see subdwarf
- B-V: see color index
- B/SN (Asiago Supernova Catalog): catalog of known supernovae and their galaxies
- B0950+08 (PSR B0950+08): young pulsar
- B1875.0
- B1900.0
- epoch B1950.0: midnight 1/1/1950 GMT as used as a time reference
- Terrestrial Time: current measure of time for astronomical observations on Earth
- B1900.0 epoch: see epoch
- B1925.0
- B1950.0 (epoch B1950.0): midnight 1/1/1950 GMT as used as a time reference
- Terrestrial Time: current measure of time for astronomical observations on Earth
- B1950.0 epoch: see epoch
- B1950.0 equinox: see J2000.0 equinox
- B1950.0 equinox: see epoch B1950.0
- B1957+20 (Black Widow Pulsar): binary system consisting of a pulsar and small companion
- B2: see Bologna Survey of Radio Sources
- B2K: see BOOMERanG
- B3: see Bologna Survey of Radio Sources
- B4R: see Large Millimeter Telescope
- BA (balanced accuracy): average of true positive and negative rates
- BA: see rare designator prefixes
- Ba star (barium star): star showing unexpected barium lines
- BA supergiant: very bright giant star
- BA-type supergiant (BA supergiant): very bright giant star
- BAA (British Astronomical Association): amateur astronomer organization
- Baade Telescope: see Magellan Telescopes
- Baade's Window: region of sky allowing observation into the galactic center
- BAAS (Bulletin of the American Astronomical Society): US professional organization's journal of record
- back end (back end instrument): instruments of a telescope that process or combine signals
- back end instrument: instruments of a telescope that process or combine signals
- back-of-the-envelope calculation: very short calculation to get a rough idea of a value
- back-yard astronomy: see amateur astronomy
- background
- Background Imaging of Cosmic Extragalactic Polarization (BICEP2): survey to measure the polarization of the CMB
- background subtraction (sky subtraction): removing background radiation from a telescope observation
- backward Fourier transform: see Fourier transform
- backward model: see forward model
- retrieval: determining parameters through observation and modeling
- Badgerys Creek 101-MHz Interferometer: see Badgerys Creek Interferometer 101-MHz Survey
- MSH Catalog: 1950s catalog of radio sources from a Mills Cross survey
- Badgerys Creek Interferometer 101-MHz Survey: early 1950s survey of southern-hemisphere radio sources
- baffle: see stray light
- Lyot stop: optical element to block unwanted light within instruments
- Bailey classification: see RR Lyrae variable
- Baksan Neutrino Observatory: Russian underground particle detector
- Baksan Underground Scintillation Telescope: see Baksan Neutrino Observatory
- BAL: see double star designation
- balanced accuracy: average of true positive and negative rates
- Balbus-Hawley Instability (magnetorotational instability): instability in the fluid of a disk from MHD effects
- Baldwin effect: relation between quasar line width and luminosity
- Balloon Observations of Millimetric Extragalactic Radiation and Geophysics (BOOMERanG): 1990s-2000s balloon-borne 1.3-meter millimeter telescope
- Balloon-borne Imaging Test-bed: see SuperBIT
- Balloon-borne Large Aperture Submillimeter Telescope (BLAST): balloon-borne 1.8-m submillimeter telescope
- Balloon-borne Ultraviolet Stellar Spectrograph (BUSS): 1970s balloon-based ultraviolet astronomy mission
- Balloon-borne Ultraviolet Stellar Spectrometer (BUSS): 1970s balloon-based ultraviolet astronomy mission
- Balmer
- Balmer series: hydrogen lines for electrons settling from n > 2 to n = 2
- Balmer break (Balmer jump): abrupt change in stellar spectrum at the Balmer series wavelength limit
- Balmer discontinuity (Balmer jump): abrupt change in stellar spectrum at the Balmer series wavelength limit
- Balmer edge (Balmer jump): abrupt change in stellar spectrum at the Balmer series wavelength limit
- Balmer jump: abrupt change in stellar spectrum at the Balmer series wavelength limit
- Balmer limit: see Balmer series
- Balmer jump: abrupt change in stellar spectrum at the Balmer series wavelength limit
- Balmer-break galaxy: a galaxy emitting very little shorter than 3646 angstroms
- Balmer series: hydrogen lines for electrons settling from n > 2 to n = 2
- Balmer jump: abrupt change in stellar spectrum at the Balmer series wavelength limit
- Balmer-break galaxy: a galaxy emitting very little shorter than 3646 angstroms
- Be star: early star with Balmer emission lines
- H-alpha: hydrogen line for electrons settling from n = 3 to n = 2
- H-beta: hydrogen line for electrons settling from n = 4 to n = 2
- hydrogen: most prominent element, atomic number 1
- Balmer's constant: see Balmer series
- Balmer-break galaxy: a galaxy emitting very little shorter than 3646 angstroms
- band (passband): range of electromagnetic wavelengths that a filter allows
- band (spectral band): set of related, closely-packed spectral lines
- band: see zone
- B: photometric filter for blue light
- extreme ultraviolet: electromagnetic radiation in the range of 10-124 nm
- extremely low frequency: electromagnetic radiation, frequency 3 Hz to 30 Hz
- far infrared: infrared radiation with wavelengths in the 30-450 μm range
- G band: band of visible light around 5100 angstroms
- gamma rays: electromagnetic radiation, wavelength 10 picometers and less
- high frequency: electromagnetic radiation, frequency 3-30 MHz
- I band: passband for near-infrared light
- infrared: light with wavelength too long for our eyes to sense
- K band: atmospheric window centered around 2.2 microns, or 136 THz
- microwave: electromagnetic radiation, frequency 300 MHz to 300 GHz
- mid infrared: infrared radiation with wavelengths in the 7.5-25 μm range
- near infrared: electromagnetic radiation in the range of 750-2500 nm
- OIR: "band name" that means both visible light and infrared
- Q band: name for EMR frequency-range on the order of 45 GHz
- R band: band of visible light around 6500 angstroms
- radio: electromagnetic radiation, frequency 3 kHz to 300 GHz
- subradio: electromagnetic radiation, frequency below 3 kHz
- super low frequency: electromagnetic radiation, frequency 30 Hz to 300 Hz
- tremendously low frequency: presumably electromagnetic radiation, frequency below 3 Hz
- U: photometric filter for ultraviolet light
- ultra low frequency: electromagnetic radiation, frequency 300 Hz to 3 kHz
- ultra-high-energy gamma rays: energetic gamma rays with more than 100 TeV photon energy
- ultraviolet: electromagnetic radiation, wavelength 10-400 nm
- UVOIR: a spectral "band name" covering UV, visible light, and IR
- V: photometric filter for visible light
- very low frequency: electromagnetic radiation, frequency 3-30 kHz
- very-high-energy gamma rays: energetic gamma rays with 100 GeV to 100 TeV photon energy
- visible light: electromagnetic radiation that our eyes can sense
- X-ray: electromagnetic radiation, wavelength 0.01 to 10 nanometers
- XEUV: electromagnetic radiation in the range of 0.15-124 nm
- band absorption
- band shifting: effect of redshift on photometry
- bandpass filter: device to filter away all but a band of frequencies
- bandwidth: number of hertz between minimum and maximum frequencies
- BAO (Beijing Astronomical Observatory): part of Chinese Academy of Sciences
- BAO (baryon acoustic oscillations): density fluctuations stemming from acoustic waves in the early universe
- BAO standard ruler: see baryon acoustic oscillations
- BAR: see double star designation
- bar: central feature of some spiral galaxies
- bar: see atm
- barium
- Am star: A-type star with metallic lines
- barium star: star showing unexpected barium lines
- barium star: star showing unexpected barium lines
- Barnard (Barnard Catalog): 1919 catalog of dark nebulae
- Barnard Catalog: 1919 catalog of dark nebulae
- Barnard Catalogue of 349 Dark Objects in the Sky (Barnard Catalog): 1919 catalog of dark nebulae
- Barnard object: see Barnard Catalog
- Barnard's Loop: emission nebula in Orion
- Barnard's Star: nearby red dwarf
- baroclinic atmosphere: see baroclinicity
- baroclinic instability: see baroclinicity
- baroclinicity: measure of misalignment of fluid density and pressure
- baroclinity (baroclinicity): measure of misalignment of fluid density and pressure
- barometric admittance (admittance): effect of atmospheric pressure on gravity
- barotropic atmosphere: see baroclinicity
- barotropy: see baroclinicity
- barred: see bar
- barred galaxy
- barred irregular galaxy: see bar
- barred irregular galaxy: see irregular galaxy
- barred lenticular galaxy: see bar
- barred spiral galaxy: see bar
- barrel distortion: distortion such that a square shows with convex edges
- barrier: challenging issue regarding planet formation
- barrier penetration (quantum tunneling): quantum mechanical effect of particles passing through a barrier
- barriers
- barycenter: center of mass of two orbiting bodies
- barycentric coordinate system (areal coordinate system): coordinate system based upon a known triangle
- barycentric coordinate time: see time standard
- barycentric coordinates: see barycenter
- barycentric dynamical time: see time standard
- barycentric Julian day: see Julian date
- baryogenesis: see antimatter
- baryon: protons, neutrons, and other three-quark particles
- baryon: see particle
- hyperon: exotic type of baryon
- neutron: type of baryon that is stable and has no electric charge
- nucleon: proton or neutron
- proton: type of baryon that is stable and has an electric charge of +1
- baryon acoustic oscillation
- baryon acoustic oscillations: density fluctuations stemming from acoustic waves in the early universe
- Baryon Acoustic Oscillations in Neutral Gas Observations (BINGO): future radio telescope for mapping distant neutral hydrogen
- baryon density parameter: see Lambda-CDM model
- Baryon Oscillation Spectroscopic Survey: survey of spatial distribution of luminous red galaxies and quasars
- baryonic gas fraction (gas fraction): fraction of a galaxy or cluster consisting of gas
- baryonic mass density: see critical density
- baryonic matter: ordinary matter made up of protons and neutrons
- baryon: protons, neutrons, and other three-quark particles
- dark matter: matter in galaxies and galaxy clusters suggested by their gravity
- baryonic Tully-Fisher relation: see Tully-Fisher relation
- Bas: see Basel Open Cluster Catalogue
- basal: from the base or from below
- basalt: an igneous rock type that shows rapid cooling
- Basel (Basel Open Cluster Catalogue): list of open clusters
- Basel Astronomical Institute
- Basel Open Cluster Catalogue: list of open clusters
- baseline: distance between dishes of an interferometer
- baseline: see parallax
- basic calibrated data: class of moderately-processed output from telescope observations
- basic transit model calculation in Python (batman): code to calculate model transit lightcurves
- basicity (acidity): measure of the activity of hydrogen ions in a solution
- BASIS (Burst and All Sky Imaging Survey): late 1990s GRB-observer satellite proposal
- basis function: one of a set of functions used to approximate a function of interest
- BASS: survey of AGNs found by the Swift BAT
- BaSTI: database relating isochrones to stellar parameters
- BaSTI isochrone: see BaSTI
- BAT: see Swift
- BASS: survey of AGNs found by the Swift BAT
- BAT6: sample of long GRBs
- BAT AGN spectroscopic survey (BASS): survey of AGNs found by the Swift BAT
- BAT6: sample of long GRBs
- BAT99: see rare designator prefixes
- BATC: photometric survey of Milky Way stars
- bathymetry: study and measurement of sea depths
- batman: code to calculate model transit lightcurves
- BATS-R-US: see SWMF
- BATSE: see Compton Gamma Ray Observatory
- BATSRUS: see SWMF
- BATTeRS (Bisei Asteroid Tracking Telescope for Rapid Survey): Japanese telescope surveying to find NEOs and space junk
- Bautz-Morgan classification: morphology classification of galaxy clusters
- BAX: see rare designator prefixes
- Bayer designation: star designation consisting of a Greek letter and constellation name
- Bayes factor: see Bayesian statistics
- Bayes' law: see Bayesian statistics
- Bayes' rule: see Bayesian statistics
- Bayes' theorem: see Bayesian statistics
- Bayesian inference: see Bayesian statistics
- Bayesian probabilities: see Bayesian statistics
- Bayesian statistics: statistics method assigning probability to your belief
- Bayesian statistics: see Markov chain Monte Carlo
- PyMC: Python package for Bayesian statistical modeling
- BAZ: see double star designation
- BB (black body): idealized object that reflects no light
- BB: see CMB polarization
- BBFS: see HEAO-2
- BBG (Balmer-break galaxy): a galaxy emitting very little shorter than 3646 angstroms
- BBH (binary black hole): pair of co-orbiting black holes
- BBN (Big Bang nucleosynthesis): creation of atomic nuclei in the very early universe
- BBSO (Big Bear Solar Observatory): US government sponsored solar observatory
- BBXRT (Broad Band X-Ray Telescope): 1990s Astro-1 Space Shuttle X-ray telescope
- BC: see rare designator prefixes
- BCD (basic calibrated data): class of moderately-processed output from telescope observations
- BCD: see dwarf galaxy classification
- BCE: see variable star
- BCEP: see variable star
- BCG (brightest cluster galaxy): a cluster's most luminous galaxy
- BCG: see dwarf galaxy
- BCool: project studying stellar magnetism
- BCS: see Ariel 5
- BCS: see Yohkoh
- BCS theory: see Cooper pair
- BCSVS: see Bibliographic Catalog of Variable Stars
- BCVS (Bibliographic Catalog of Variable Stars): listing of references to variable stars
- BD (Bonner Durchmusterung Catalog): well-known astrometric catalog from late 1800s
- BD (brown dwarf): star-like object with less mass than a star
- BD: see dropout
- BD+36 2147 (Lalande 21185): nearby red dwarf
- BD+47 2846: see HAT-P-7b
- BD+47 2846b (HAT-P-7b): hot Jupiter discovered in 2008
- BDF: field used in search for distant galaxies
- BDS (Burnham Double Star Catalogue): 1906 catalog with multiple star systems and non-orbiting double stars
- BDS03: see rare designator prefixes
- Be (Berkeley Open Cluster Catalogue): list of open clusters
- Be star: early star with Balmer emission lines
- Achernar: ninth-brightest star in the sky
- shell star: type of star with broad and narrow absorption lines
- Be X-ray binary: see X-ray binary
- beaded curtain: see ssDNA
- Beagle 2: see Mars Express
- beam: portion of a sky that a radio telescope is viewing
- beam: see equation of radiative transfer
- CLEAN: algorithm to extract usable images from interferometry-produced images
- dirty image: image that includes the distortions of the beam and sampling
- beam pattern: see beam
- beam width: see beam
- beamforming: see beam
- beaming
- BearCLAW
- BEAST: survey of B stars for possible exoplanets
- beat frequency: frequency emerging from two other frequencies
- BEC (Bose-Einstein condensate): rare state of matter possible at cryogenic temperatures
- Becker, White, and Edwards Catalog: 1990s radio catalog from a Green Bank 300ft Telescope survey
- BEFS (Berkeley Extreme and Far-UV Spectrometer): 1990s UV spectrometer used on two Space Shuttle missions
- Beijing Astronomical Observatory: part of Chinese Academy of Sciences
- Beijing-Arizona-Taiwan-Connecticut Survey (BATC): photometric survey of Milky Way stars
- Bekenstein engine (Geroch-Bekenstein engine): hypothetical engine to overcome thermodynamics laws using a black hole
- BEL: broad emission line
- BEL region (broad line region): AGN region producing broader lines
- Belgian
- TRAPPIST: a ground-based automated transiting-planet finding telescope
- Belgium
- bell curve
- Bellatrix
- Orion: well-known constellation in the northern hemisphere
- belt: see zone
- jet stream: upper-atmosphere narrow west-to-east streams of air
- superrotating wind: wind traveling in the same direction as the planet is rotating
- Bennett: see rare designator prefixes
- Bennu (101955 Bennu): near-Earth asteroid that is the target of a sample-return mission
- bent jet: see jet
- benzene: see hydrocarbon
- BepiColombo: mission to Mercury
- Mercury: inner-most and smallest planet in the solar system
- BeppoSAX: Italian-Dutch space X-ray telescope
- Berkeley: see Berkeley Open Cluster Catalogue
- PAPER: radio interferometer for 21-cm measurement
- Berkeley Extreme and Far-UV Spectrometer: 1990s UV spectrometer used on two Space Shuttle missions
- Berkeley Lab (Lawrence Berkeley National Laboratory): US energy-related physics laboratory
- Berkeley Open Cluster Catalogue: list of open clusters
- Berkeley-Illinois-Maryland Association: operator of 1980s-2000s radio telescope
- Bernard Lyot Telescope
- Bernes: see rare designator prefixes
- Bernstein polynomial: polynomial form capable of producing arbitrary shapes
- beryllium
- Besselian date: see epoch
- Besselian epoch: see epoch B1950.0
- Besselian year: see epoch B1950.0
- beta: ratio of plasma pressure to magnetic pressure
- Beta Canis Majoris star: see variable star
- Beta Centauri: second brightest star in Centaurus
- Beta Cephei variable: see variable star
- beta decay: radioactivity such that an electron or positron is emitted
- beta drift: tendency for a cyclone to drift poleward and westward
- beta effect (beta drift): tendency for a cyclone to drift poleward and westward
- Beta Lyrae variable: see variable star
- Beta Orionis (Rigel): brightest star in constellation Orion
- beta particle: see beta decay
- Beta Per (Algol): a multiple-star system demonstrating effects of mass transfer
- Beta Persei (Algol): a multiple-star system demonstrating effects of mass transfer
- Beta Pictoris
- Beta Pictoris b: super-Jupiter discovered in 2008
- beta plane: see Coriolis force
- beta rays: see beta decay
- beta-decay stable isobars (valley of beta stability): set of isotopes not prone to beta decay
- Betelgeuse: second brightest star in constellation Orion
- Orion: well-known constellation in the northern hemisphere
- bethe (foe): unit of energy on the order of a supernova's output
- Bethe-Heitler cross section: see Bethe-Heitler process
- Bethe-Heitler formula: see Bethe-Heitler process
- Bethe-Heitler pair production: see Bethe-Heitler process
- Bethe-Heitler process: type of pair production interaction near nuclei
- BeXRB: see X-ray binary
- BF
- BFI: see Big Bear Solar Observatory
- BFS: see rare designator prefixes
- BG: see rare designator prefixes
- BG4
- BlackGEM: telescope array to follow up gravitational wave signals
- BH (black hole): region of such high mass that light cannot escape
- BH: see rare designator prefixes
- BH mass gap: see stellar-mass black hole
- BH merger (black hole merger): two black holes meeting and forming one
- BH merger.binary supermassive black hole
- BH model (black hole model): description of a BH using math or computation
- BHAD: see accretion disk
- BHAR (black hole accretion rate): measure, especially used for AGNs
- BHB (black hole binary): binary star in which one is a stellar black hole
- BHB (blue horizontal branch): blue end of the horizontal branch
- BHC (BlackHoleCam): European project to study black holes
- BHJ: see rare designator prefixes
- BHM: see Sloan Digital Sky Survey
- BHMF (black hole mass function): mass of the distribution of black holes
- BHNS merger (neutron-star black-hole merger): a neutron star falling into a black hole
- BHR: see rare designator prefixes
- BHXRT: see transient
- BHXT: see transient
- BI: see rare designator prefixes
- BIA (Black in Astro): advocacy initiative
- bias (selection bias): selection of a sample set that is not appropriately randomized
- bibcode: reference code for a journal article
- Bibliographic Catalog of Suspected Variable Stars: see Bibliographic Catalog of Variable Stars
- Bibliographic Catalog of Variable Stars: listing of references to variable stars
- Bica: see rare designator prefixes
- bicarbonate
- acidity: measure of the activity of hydrogen ions in a solution
- carbonate system: system governing water and CO2 in the presence of each other
- BICEP: see BICEP2
- BICEP Array: see BICEP2
- BICEP2: survey to measure the polarization of the CMB
- BICEP3: see BICEP2
- Biden: see Kuiper Belt
- Big Bang: theoretical event when the universe expanded from a point
- Big Bang nucleosynthesis: creation of atomic nuclei in the very early universe
- Big Bang theory: see Big Bang
- Big Bear Solar Observatory: US government sponsored solar observatory
- Big Bounce: see Big Crunch
- Big Crunch: theoretical end of universe drawn together by gravity
- Big Ear
- Big Freeze: see Big Crunch
- Big Rip: see Big Crunch
- Big Slurp: see Big Crunch
- BigBOSS: BOSS survey follow-on
- BigBOSS Spectrograph
- Bigelow Sky Survey: see Catalina Sky Survey
- bigravity: modifications to GR defining two metrics
- BIMA (Berkeley-Illinois-Maryland Association): operator of 1980s-2000s radio telescope
- BIMA radio telescope array (BIMA telescope): millimeter interferometer in operation 1985 to 2005
- BIMA telescope: millimeter interferometer in operation 1985 to 2005
- bimetric gravity (bigravity): modifications to GR defining two metrics
- binary (binary star): system of two stars co-orbiting
- binary asteroid: see binary minor planet
- binary black hole: pair of co-orbiting black holes
- binary black hole formation channel: see binary black hole
- binary burning
- binary companion: one of the two stars of a binary star
- binary companion: see binary star
- binary mass function (mass function): measure of binaries that constrains the masses
- binary minor planet: minor planet with another body orbiting it
- binary neutron star: two neutron stars co-orbiting
- Binary Population and Spectral Synthesis (BPASS): evolution and population synthesis code for binary stars
- binary population synthesis: see stellar population synthesis
- binary pulsar: see binary neutron star
- binary SMBH: co-orbiting supermassive black holes
- binary star: system of two stars co-orbiting
- binary star type
- binary stars
- Binary Stellar Evolution (BSE): a code to model the evolution of a binary star system
- binary supermassive black hole (binary SMBH): co-orbiting supermassive black holes
- binary system (binary star): system of two stars co-orbiting
- binary TD: see neutron star merger
- binary tidal deformability: see neutron star merger
- binary TNO: see binary minor planet
- binary trans-Neptune object: see binary minor planet
- binary X-ray pulsar (X-ray pulsar): pulsar producing X-rays from accretion
- pulsar: type of astronomical body with EMR in regular cycles of seconds or less
- binary X-ray system (X-ray binary): binary star emitting X-rays
- binary YORP: see Yarkovsky-O'Keefe-Radzievskii-Paddack effect
- binary-star companion (binary companion): one of the two stars of a binary star
- binding energy: energy needed to separate two objects
- BINGO: future radio telescope for mapping distant neutral hydrogen
- binomial coefficients
- BINOSPEC: see MMT
- biofluorescence: common fluorescence in organisms to dissipate harmful UV radiation
- fluorescence: emission from a molecule excited by absorption
- biology
- astrobiology: study of extra-terrestrial life
- CHNOPS: six common elements in biological molecules
- CHON: four common elements in biological molecules
- glycine: smallest of the twenty common amino acids
- mass extinction: event in which many species went extinct
- molecular handedness: mirror-imaged variants of some molecules
- ssDNA: DNA without the double strand
- water activity: measure of partial vapor pressure of water
- biomarker (biosignature): sign of life
- biosignature: sign of life
- bipolar jets: see bipolar outflow
- bipolar outflow: streams of matter from the poles of a protostar
- birefringent: see waveplate
- Birkhoff's theorem: shows GR qualities of a spherically-symmetric mass
- BIS (British Interplanetary Society): space-exploration/research advocacy organization
- Bisei Asteroid Tracking Telescope for Rapid Survey: Japanese telescope surveying to find NEOs and space junk
- bispectrum: see N-point function
- bispectrum analysis (speckle masking): speckle suppression technique using a calculation of the bispectrum
- BIT: see SuperBIT
- BITP (Bogolyubov Institute for Theoretical Physics): Ukrainian research institute
- Biurakan: see rare designator prefixes
- BJ (Balmer jump): abrupt change in stellar spectrum at the Balmer series wavelength limit
- BJD: barycentric Julian day
- BJD: see Julian date
- BK: see rare designator prefixes
- BK metric
- BL (Breakthrough Listen): SETI survey using GBT and Parkes Observatory
- BL: see NIRCam
- BL: see spectral line designation
- BL Lac object: see blazar
- BL Lacertae: see blazar
- black body: idealized object that reflects no light
- black dwarf: see brown dwarf
- black dwarf: see white dwarf
- Black Eye Galaxy (M64): nearby dusty galaxy
- black hole: region of such high mass that light cannot escape
- GRS 1915+105: stellar-mass black hole microquasar
- GW detection: observed gravitational wave signal recognizable as an astronomical event
- LB-1: binary star with evidence of a black hole
- M87*: SMBH at the center of galaxy M87
- Sag A*: SMBH at the center of Milky Way
- black hole accretion disk: see accretion disk
- black hole accretion rate: measure, especially used for AGNs
- black hole binary: binary star in which one is a stellar black hole
- black hole candidate
- black hole flare (tidal disruption event): star pulled apart by black hole tidal forces
- Black Hole Mapper: see Sloan Digital Sky Survey
- black hole mass function: mass of the distribution of black holes
- black hole mass gap: see stellar-mass black hole
- black hole mechanics (black hole thermodynamics): science of black holes
- black hole merger: two black holes meeting and forming one
- black hole model: description of a BH using math or computation
- black hole shadow: dark-disk appearance of a black hole viewed from a distance
- black hole thermodynamics: science of black holes
- black hole type
- black hole X-ray transient: see transient
- black holes
- Black in Astro: advocacy initiative
- black star: theoretical alternative to black holes
- Black Widow Pulsar: binary system consisting of a pulsar and small companion
- black-body radiation: EMR with a characteristic spectrum due to the temperature of a body
- black-body spectrum: see black-body radiation
- black-body temperature (effective temperature): temperature of an equivalent black body in terms of total radiation
- black-body temperature: see black-body radiation
- black-hole information paradox: a behavior of black holes that appears to contradict physics
- black-hole neutron-star merger (neutron-star black-hole merger): a neutron star falling into a black hole
- blackbody (black body): idealized object that reflects no light
- BlackGEM: telescope array to follow up gravitational wave signals
- BlackHoleCam: European project to study black holes
- BLAGN: see active galactic nucleus
- BLANCA
- CASA-MIA: 1990s cosmic-ray detector in Utah
- Blanco 4M
- Blanco 4m (Víctor M. Blanco Telescope): 4 meter reflector telescope in Chile
- Blandford-Payne mechanism: means of by which an accretion disk can power a jet
- Blandford-Payne process (Blandford-Payne mechanism): means of by which an accretion disk can power a jet
- Blandford-Znajek mechanism: means of extracting BH rotational energy by magnetized accretion disk
- Penrose process: process by which energy can be extracted from black hole's rotation
- Blandford-Znajek process (Blandford-Znajek mechanism): means of extracting BH rotational energy by magnetized accretion disk
- blanketing effect (line blanketing): so many bunched spectral lines that they cannot be distinguished
- BLAST: balloon-borne 1.8-m submillimeter telescope
- BLAST Observatory: see BLAST
- BLAST-TNG: see BLAST
- BLASTPol: see BLAST
- blastwave: spherical shock wave from a small volume
- blazar: very compact variable quasar
- blazars
- blaze angle: see grating
- blazed grating: see grating
- blend analysis: see blended spectra
- Blendanal
- blended spectra: an observed spectrum comprising light from multiple objects
- blended spectra: an observed spectrum comprising light from multiple objects
- Blender
- blended spectra: an observed spectrum comprising light from multiple objects
- BLG: see OGLE
- blind analysis: performing experimental analysis without knowing the data
- blind survey: survey conducted independently of prior information
- blink: see comparator
- blink comparator (comparator): device to compare the position of objects on plates
- blink microscope (comparator): device to compare the position of objects on plates
- blitzar: see hypermassive neutron star
- BLL: see blazar
- BLLAC: see blazar
- Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme: see SWMF
- BLONG: see NIRCam
- blow off: see atmospheric escape
- blowoff: see hydrodynamic escape
- BLR (broad line region): AGN region producing broader lines
- BLRG: see radio galaxy
- blue: see globular cluster
- B: photometric filter for blue light
- blue and new: see red and dead
- blue compact dwarf galaxy: see dwarf galaxy classification
- blue compact galaxy: see dwarf galaxy
- blue dropout galaxy: see dropout
- blue galaxy: see galaxy main sequence
- blue giant: see giant star
- B-type star: star with spectral characteristics of around 10000-30000 K
- red giant: very bright red star
- blue horizontal branch: blue end of the horizontal branch
- blue hypergiant: see hypergiant
- blue kilonova: see kilonova
- blue kilonova model: see kilonova
- blue noise: see red noise
- blue quasar: see quasar
- blue shift: shortening of wavelengths due to Doppler effects
- Doppler shift: wave frequency difference due to relative velocity difference with source
- line broadening: processes causing a spectral line to have width
- P Cygni profile: emission-line shape including a blue-shifted absorption feature
- redshift: change to longer wavelengths due to Doppler effects
- blue straggler: see turn-off point
- open cluster: group of stars within a galaxy apparently formed by a single cloud
- blue supergiant: see supergiant
- B-type star: star with spectral characteristics of around 10000-30000 K
- blueshift (blue shift): shortening of wavelengths due to Doppler effects
- Doppler shift: wave frequency difference due to relative velocity difference with source
- redshift: change to longer wavelengths due to Doppler effects
- BlueTides: see Astrid simulation
- BMP (binary minor planet): minor planet with another body orbiting it
- BNO (Baksan Neutrino Observatory): Russian underground particle detector
- BNS (binary neutron star): two neutron stars co-orbiting
- BNSC (British National Space Centre): the older name for UKSA
- Bo: see Bologna Catalog of Globular Clusters
- Boötes Field: moderate size survey field
- Boötes I
- Boötes II
- Boötes III
- BOAO (Bohyunsan Optical Astronomy Observatory): on Bohyeon Mountain, Korea
- BOAT: brightest of all time
- Bochum: see rare designator prefixes
- Bode designation: see Flamsteed designation
- Bode's law (Titius-Bode law): relationship between the distances between solar system planets
- body (astronomical object): planet, star, galaxy, etc.
- BOE (Butcher-Oemler effect): observation of more blue galaxies at z > 0.3
- Bogolyubov Institute for Theoretical Physics: Ukrainian research institute
- Bohr model: has electrons circling nucleus in quantized orbits
- Bohr model of the atom (Bohr model): has electrons circling nucleus in quantized orbits
- Bohr radius: see Bohr model
- Bohyunsan Optical Astronomy Observatory: on Bohyeon Mountain, Korea
- boil off: see Jeans escape
- Bok: see rare designator prefixes
- Bok 2.3m Telescope: see Kitt Peak National Observatory
- Bok globule: dense molecular cloud
- Bok Telescope
- Bol (Bologna Catalog of Globular Clusters): catalog of globular clusters in M31
- Bol'shoi Teleskop Azimultal'nyi (Large Altazimuth Telescope): 6-meter reflector telescope in Russia
- bolide: see meteoroid
- Bolocam: see Caltech Submillimeter Observatory
- Bologna Catalog of Globular Clusters: catalog of globular clusters in M31
- Bologna Sky Survey (Bologna Survey of Radio Sources): 1970s-1980s radio survey
- Bologna Survey (Bologna Survey of Radio Sources): 1970s-1980s radio survey
- Bologna Survey of Radio Sources: 1970s-1980s radio survey
- bolometer: instrument measuring heat produced by radiation
- GISMO: 2 mm bolometer camera on IRAM 30 m telescope
- MUSTANG: bolometer array on the Green Bank Telescope
- SCUBA: submillimeter instrument on James Clark Maxwell Telescope
- bolometers
- ACBAR: instrument used in a CMB survey
- bolometric
- bolometer: instrument measuring heat produced by radiation
- bolometric correction: difference between an object's bolometric and visual magnitudes
- bolometric luminosity: total luminosity of an object at all wavelengths
- bolometric magnitude: absolute magnitude of all wavelengths
- Bolshoi simulation: cosmological simulation
- Boltzmann code: see CMBFAST
- Boltzmann constant: relates particle energy and temperature
- Boltzmann distribution
- Boltzmann equation: equation relating atomic excitation to temperature
- Boltzmann equation (Boltzmann transport equation): equation for evolving distribution of gas particles
- Boltzmann factor: see Boltzmann equation
- Boltzmann relation (Boltzmann equation): equation relating atomic excitation to temperature
- Boltzmann solver: see CMBFAST
- Boltzmann transport equation: equation for evolving distribution of gas particles
- Bond: see rare designator prefixes
- bond
- Bond albedo: see albedo
- Bondi accretion
- Bondi radius: radius within which a body moving through a medium will draw it in
- Bondi radius: radius within which a body moving through a medium will draw it in
- Bondi-Hoyle accretion
- Bondi radius: radius within which a body moving through a medium will draw it in
- Bondi-Hoyle radius (Bondi radius): radius within which a body moving through a medium will draw it in
- Bondi-Hoyle-Lyttleton accretion
- Bondi radius: radius within which a body moving through a medium will draw it in
- Bondi-Hoyle-Lyttleton radius (Bondi radius): radius within which a body moving through a medium will draw it in
- bone
- filament: linear volume of high molecular gas density within a galaxy
- Bonner Durchmusterung Catalog: well-known astrometric catalog from late 1800s
- BOOM01: see BOOMERanG
- BOOM05: see BOOMERanG
- BOOMERanG: 1990s-2000s balloon-borne 1.3-meter millimeter telescope
- BOOMERanG 2005: see BOOMERanG
- Borexino: European underground neutrino observatory
- BoRG: see rare designator prefixes
- born again star: see asymptotic giant branch
- Boron Solar Neutrino Experiment (Borexino): European underground neutrino observatory
- Bose-Einstein condensate: rare state of matter possible at cryogenic temperatures
- Bose-Einstein distribution (Bose-Einstein statistics): possible distribution of particles not bound by Pauli exclusion
- Bose-Einstein statistics: possible distribution of particles not bound by Pauli exclusion
- boson: see particle
- boson star: see exotic star
- BOSS (Baryon Oscillation Spectroscopic Survey): survey of spatial distribution of luminous red galaxies and quasars
- Boss General Catalog: 1936 catalog of 30,000 stars
- BOSS Spectrograph: see Sloan 2.5m Telescope
- bottom: see flavor
- bottom quark: see particle
- bottom quark: see quark
- bottom up model: see galaxy formation
- Bouguer anomaly: gravity's local variation after compensating for altitude and landforms
- Bouguer correction: see Bouguer anomaly
- Bouguer reduction: see Bouguer anomaly
- bouncing barrier: the problem that the seeds of planets would rebound rather than merge
- bouncing barrier: see meter size barrier
- barrier: challenging issue regarding planet formation
- bound GMC: see giant molecular cloud
- bound-bound
- bound-free
- boundary condition
- bow shock: shock wave of a magnetosphere through the surrounding medium
- Boyajian's Star (KIC 8462852): star with unusual variations
- Boyden Observatory 1.5 m telescope
- Boyle's law
- BP Crucis
- BP process (Blandford-Payne mechanism): means of by which an accretion disk can power a jet
- Bp star: see Ap star
- Bp-Ap: see chemically peculiar star
- BP/RP: see Gaia
- BPASS: evolution and population synthesis code for binary stars
- BPI: see rare designator prefixes
- BPM (Bruce Proper Motion Survey): 1941 southern-hemisphere survey catalog of Luyten's
- BPM: see rare designator prefixes
- BPMA: see rare designator prefixes
- BPS: see HK Survey
- BPS: see stellar population synthesis
- BPT diagram: diagram comparing emission-line ratios for characterizing ionization
- BR: see rare designator prefixes
- bracket abundance notation (bracket notation): notation for a comparison of an abundance ratio with that of the Sun
- bracket notation: notation for a comparison of an abundance ratio with that of the Sun
- Brackett
- Brackett series: hydrogen lines for electrons settling from n > 4 to n = 4
- hydrogen: most prominent element, atomic number 1
- Bradley: see rare designator prefixes
- braking index: see pulsar characteristic age
- braking radiation (bremsstrahlung): photon emission when a charged particle is decelerated
- BRAN: see rare designator prefixes
- brane: mathematical object with dimensions
- brane cosmology: see brane
- brane world cosmology: see brane
- Brazil
- BRC: see rare designator prefixes
- break-up velocity: see stellar rotation
- breaking a degeneracy: see degeneracy
- breaking atmospheric wave
- Breakthrough Initiatives
- Breakthrough Listen: SETI survey using GBT and Parkes Observatory
- Breakthrough Starshot (Starshot): plan for mission to fly by Alpha Centauri
- bremsstrahlung: photon emission when a charged particle is decelerated
- bremsstrahlung cooling: see thermal bremsstrahlung
- bremsstrahlung self-absorption: see thermal bremsstrahlung
- Brey: see rare designator prefixes
- Brh: see rare designator prefixes
- BRI: see rare designator prefixes
- bright giant: see giant star
- bright nebula: cloud that gives off or reflects light
- bright star
- Achernar: ninth-brightest star in the sky
- Alpha Centauri: nearest star system
- Arcturus: fourth brightest star in the sky
- Beta Centauri: second brightest star in Centaurus
- Betelgeuse: second brightest star in constellation Orion
- Canopus: second brightest star in the sky
- Capella: brightest star in Auriga
- Epsilon Eridani: third nearest visible star system in sky
- Procyon: brightest star in Canis Minor
- Rigel: brightest star in constellation Orion
- Sirius: brightest star in the sky
- Vega: brightest star in constellation Lyra
- Bright Star Catalog: early 20th century catalog of 9000 stars
- bright supergiant: see supergiant
- brightest cluster galaxy: a cluster's most luminous galaxy
- brightest star
- brightness (intensity): power reaching a surface from a specific source
- brightness temperature: temperature of an equivalent black body in terms of spectral radiance
- British
- British Astronomical Association: amateur astronomer organization
- British Columbia
- British Interplanetary Society: space-exploration/research advocacy organization
- British National Space Centre: the older name for UKSA
- broad band: see passband
- broad band filter: see passband
- broad band photometry: see photometry
- Broad Band X-Ray Telescope: 1990s Astro-1 Space Shuttle X-ray telescope
- broad emission-line region (broad line region): AGN region producing broader lines
- Broad Lateral Non-imaging Cherenkov Array
- CASA-MIA: 1990s cosmic-ray detector in Utah
- broad line
- broad line AGN
- broad line region: AGN region producing broader lines
- broad-line radio galaxy: see radio galaxy
- broadband: see bandwidth
- broadening (line broadening): processes causing a spectral line to have width
- broadening function
- brown dwarf: star-like object with less mass than a star
- brown dwarfs
- Brown noise (red noise): noise tending toward lower frequencies
- Brownian motion
- red noise: noise tending toward lower frequencies
- Brownian noise (red noise): noise tending toward lower frequencies
- BRS: see double star designation
- BrsO: see double star designation
- BRT: see double star designation
- Bruce Proper Motion Survey: 1941 southern-hemisphere survey catalog of Luyten's
- Brun: see rare designator prefixes
- Brunt-Väisälä frequency: natural frequency of buoyancy waves
- brute force: see numerical methods
- BS (Bright Star Catalog): early 20th century catalog of 9000 stars
- BS: see NIRCam
- BS: see turn-off point
- open cluster: group of stars within a galaxy apparently formed by a single cloud
- BSC: see Bright Star Catalog
- BSD: see rare designator prefixes
- BSDL: see rare designator prefixes
- BSE: a code to model the evolution of a binary star system
- BSE (bulk silicate earth): the early overall composition of the silicate part of Earth
- BSG: see supergiant
- BSHORT: see NIRCam
- BSM: see bulk silicate earth
- BSMBH (binary SMBH): co-orbiting supermassive black holes
- BSO: see double star designation
- BSO: see rare designator prefixes
- BSS: see Catalina Sky Survey
- BSS: see turn-off point
- open cluster: group of stars within a galaxy apparently formed by a single cloud
- BT-Settl: model atmosphere of small stars and brown dwarfs
- BTA-6 (Large Altazimuth Telescope): 6-meter reflector telescope in Russia
- BTE (Boltzmann transport equation): equation for evolving distribution of gas particles
- BTFR: see Tully-Fisher relation
- BTU: see energy
- Btz: see rare designator prefixes
- BU: see Burnham Double Star Catalogue
- bubble: see shell
- bubble chamber
- buckminsterfullerene: see polycyclic aromatic hydrocarbon
- bucky ball: see polycyclic aromatic hydrocarbon
- bulge: denser group of stars within a larger group
- bulk: see brane
- bulk atmosphere: see atmosphere
- bulk density: total mass divided by total volume
- bulk metallicity
- bulk modulus: see sound speed
- bulk planetary atmosphere: see atmosphere
- bulk silicate earth: the early overall composition of the silicate part of Earth
- bulk silicate Mars: see bulk silicate earth
- Bullet Cluster: two galaxy clusters that are colliding
- dark matter: matter in galaxies and galaxy clusters suggested by their gravity
- Bulletin of the American Astronomical Society: US professional organization's journal of record
- bump: see superluminous supernova
- bumpy Kerr metric
- buoyancy frequency (Brunt-Väisälä frequency): natural frequency of buoyancy waves
- BUP: see rare designator prefixes
- Burnham: see Burnham Double Star Catalogue
- Burnham Double Star Catalogue: 1906 catalog with multiple star systems and non-orbiting double stars
- burning: see fusion
- burst (gravitational-wave memory): a gravitational wave that does not return
- Burst and All Sky Imaging Survey: late 1990s GRB-observer satellite proposal
- Burst Array Telescope: see BASS
- burst gravitational wave: see gravitational-wave memory
- BUSS: 1970s balloon-based ultraviolet astronomy mission
- BUST: see Baksan Neutrino Observatory
- Butcher-Oemler effect: observation of more blue galaxies at z > 0.3
- BV: see rare designator prefixes
- BVD: see rare designator prefixes
- BVIT: see Southern African Large Telescope
- BWE (Becker, White, and Edwards Catalog): 1990s radio catalog from a Green Bank 300ft Telescope survey
- BY: see variable star
- BY Draconis star: see variable star
- BY Draconis variable: see variable star
- BYORP: see Yarkovsky-O'Keefe-Radzievskii-Paddack effect
- Byurakan Observatory
- BZ: see Roma-BZCAT
- BZ process (Blandford-Znajek mechanism): means of extracting BH rotational energy by magnetized accretion disk
- BZB: see Roma-BZCAT
- BzK: see rare designator prefixes
- BZQ: see Roma-BZCAT
- BZU: see Roma-BZCAT
- B[e] star: see Be star
Index