Term Index (B)

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Term Index (B)

B: photometric filter for blue light
- B-type star (B): type of star with about 10 times the mass of the Sun
- Barnard Catalog (Barnard,B): 1919 catalog of dark nebulae
- magnetic flux (B): total magnetism passing through a surface
- magnetic flux density (B): vector field describing magnetism in relation to the Lorentz force
B field:
- magnetic flux density (B): vector field describing magnetism in relation to the Lorentz force
B(e) star:
- Be star: early star with Balmer emission lines
B-band:
- Hubble Ultra-Deep Field (HUDF): extremely detailed HST image of a small region of space
B-class:
- B-type star (B): type of star with about 10 times the mass of the Sun
B-E statistics:
- Bose-Einstein statistics: possible distribution of particles not bound by Pauli exclusion
B-mode:
- CMB polarization: effects of scattering and lensing on the CMB
- POLARBEAR: instrument to map CMB polarization
- polarization modes: electric and magnetic aspects of the polarization of electromagnetic radiation
B-type star (B): type of star with about 10 times the mass of the Sun
B-V:
- color index: a number that characterizes the color of an object
B/SN:
- Asiago Supernova Catalog (B/SN): 1999 catalog of known supernovae and their galaxies
B1875.0:
- epoch B1950.0: midnight 1/1/1950 GMT as used as a time reference
B1900.0:
- epoch B1950.0: midnight 1/1/1950 GMT as used as a time reference
- terrestrial time (TT): current measure of time for astronomical observations on Earth
B1900.0 epoch:
- epoch: when an object was at a particular set of celestial coordinates
B1925.0:
- epoch B1950.0: midnight 1/1/1950 GMT as used as a time reference
B1950.0:
- epoch B1950.0: midnight 1/1/1950 GMT as used as a time reference
- terrestrial time (TT): current measure of time for astronomical observations on Earth
B1950.0 epoch:
- epoch: when an object was at a particular set of celestial coordinates
B1950.0 equinox:
- J2000.0 equinox: equinox as of the J2000.0 epoch used as a positional reference
B1957+20:
- Black Widow Pulsar (B1957+20, PSR J1959+2048, PSR B1957+20): binary system consisting of a pulsar and small companion
B2:
- Bologna Survey of Radio Sources: 1970s-1980s radio survey
B3:
- Bologna Survey of Radio Sources: 1970s-1980s radio survey
Baade Telescope:
- Magellan Telescopes: pair of 6.5m optical telescopes in Chile
Baade's Window: region of sky allowing observation into the galactic center
BAC:
- Astrographic Catalog (AC): historical star catalog of the whole sky to magnitude 11
back end:
- front end instrument: instruments of a telescope that detect and encode the signal
back end instrument: instruments of a telescope that process or combine signals
background:
- cosmic background radiation (CBR): electromagnetic radiation coming from every direction
- cosmic gamma ray background (CGB): gamma-ray radiation seen everywhere
- cosmic infrared background (CIB): widespread infrared radiation not associated with known sources
- cosmic microwave background (CMB): microwave radiation coming from every direction
- cosmic optical background (COB): widespread optical radiation not associated with known sources
- cosmic X-ray background (CXB,CXRB): X-ray radiation coming from outside the Milky Way
- diffuse emission: electromagnetic radiation not confined to a point source
- extragalactic background light (EBL): electromagnetic radiation from star formation and AGNs
Background Imaging of Cosmic Extragalactic Polarization:
- BICEP2: survey to measure the polarization of the CMB
backward Fourier transform:
- Fourier transform: systematic method of breaking down functions into periodic components
backward model:
- forward model: model producing potential observable values from parameters
Badgerys Creek 101MHz Interferometer:
- Badgerys Creek Interferometer 101MHz Survey (Mills): early 1950s survey of southern-hemisphere radio sources
Badgerys Creek Interferometer 101MHz Survey (Mills): early 1950s survey of southern-hemisphere radio sources
baffle:
- Lyot stop: optical element to block unwanted light within instruments
- stray light: unintended light reaching a telescope's sensors
Balbus-Hawley Instability:
- magnetorotational instability (MRI): instability in the fluid of a disk from MHD effects
Balloon Observations of Millimetric Extragalactic Radiation and Geophysics:
- BOOMERanG: 1990s-2000s balloon-borne 1.3 meter millimeter telescope
Balloon-borne Large Aperture Submillimeter Telescope:
- BLAST: balloon-borne 1.8m submillimeter telescope
Balmer:
- Balmer series: hydrogen lines for electrons settling from n > 2 to n = 2
Balmer discontinuity:
- Balmer jump: abrupt change in stellar spectrum at end of Balmer series
Balmer jump: abrupt change in stellar spectrum at end of Balmer series
Balmer limit:
- Balmer-break galaxy (BBG): 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 end of Balmer series
- Balmer-break galaxy (BBG): a galaxy emitting very little shorter than 3646 angstroms
- Be star: early star with Balmer emission lines
- H-alpha (Ha,Hα, H-α): hydrogen line for electrons settling from n = 3 to n = 2
Balmer's constant:
- Balmer series: hydrogen lines for electrons settling from n > 2 to n = 2
Balmer-break galaxy (BBG): a galaxy emitting very little shorter than 3646 angstroms
band:
- B: photometric filter for blue light
- 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
- G band: band of visible light around 5100 angstroms
- gamma rays: electromagnetic radiation, wavelength 10 picometers and less
- I band: photometric filter for near infrared light
- infrared (IR): electromagnetic radiation, wavelength .74-300 micrometers
- K band: atmospheric window centered around 2.2 microns, or 136 THz
- 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
- passband: range of electromagnetic wavelengths that a filter allows
- R band: band of visible light around 6500 angstroms
- radio: electromagnetic radiation, frequency 3kHz to 300GHz
- spectral band: set of related, closely-packed spectral lines
- 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
- U: photometric filter for ultraviolet light
- 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
- V: photometric filter for visible light
- 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
- X-ray: electromagnetic radiation, wavelength .01 to 10 nanometers
- XEUV: electromagnetic radiation in the range of .15nm-400nm
- zone: apparent "horizontal" band in an atmosphere
band absorption:
- continuous absorption: the absorption of a whole section of a spectrum
band shifting: effect of redshift on photometry
bandpass filter:
- filter: optical device to filter out part of the EMR spectrum
bandwidth: number of hertz between minimum and maximum frequencies
BAO:
- baryon acoustic oscillations (BAO): density fluctuations stemming from acoustic waves in the early universe
- Baryon Oscillation Spectroscopic Survey (BOSS): survey of spatial distribution of luminous red galaxies and quasars
- BigBOSS: BOSS survey follow-on
BAO standard ruler:
- baryon acoustic oscillations (BAO): density fluctuations stemming from acoustic waves in the early universe
bar: central feature of some spiral galaxies
- atm: unit of pressure
barium:
- Am star: A-type star with metallic lines
barium star:
- binary star: system of two stars co-orbiting
Barnard:
- Barnard Catalog (Barnard,B): 1919 catalog of dark nebulae
Barnard Catalog (Barnard,B): 1919 catalog of dark nebulae
Barnard Catalogue of 349 Dark Objects in the Sky:
- Barnard Catalog (Barnard,B): 1919 catalog of dark nebulae
Barnard object:
- Barnard Catalog (Barnard,B): 1919 catalog of dark nebulae
Barnard's Star: nearby red dwarf
baroclinic atmosphere:
- baroclinicity: measure of misalignment of fluid density and pressure
baroclinic instability:
- baroclinicity: measure of misalignment of fluid density and pressure
baroclinicity: measure of misalignment of fluid density and pressure
barotropic atmosphere:
- baroclinicity: measure of misalignment of fluid density and pressure
barred:
- bar: central feature of some spiral galaxies
- spiral galaxy: flat galaxy with spiraling arms
barred galaxy:
- galaxy classification: morphological classification of galaxies
- spiral galaxy: flat galaxy with spiraling arms
barred spiral galaxy:
- bar: central feature of some spiral galaxies
barrier: challenging issue regarding planet formation
- bouncing barrier: the problem that the seeds of planets would rebound rather than merge
- kilometer size barrier: a barrier to accretion on the order of a kilometer diameter
- meter size barrier: a barrier to planet formation on the order of a meter diameter
- radial-drift barrier: the problem that forming planets would drift inward into the star
barrier penetration:
- quantum tunneling: quantum mechanical effect of particles passing through a barrier
barriers:
- planet formation: process by which planets form
barycenter: center of mass of two orbiting bodies
barycentric:
- barycenter: center of mass of two orbiting bodies
barycentric coordinate time:
- time standard: method of designating points in time and quantifying time periods
barycentric coordinates:
- barycenter: center of mass of two orbiting bodies
barycentric dynamical time:
- time standard: method of designating points in time and quantifying time periods
barycentric Julian day BJD:
- Julian date (JD): time in days since noon UT November 24 4714 BC Gregorian
baryogenesis:
- antimatter: similar to normal matter but with opposite electrical charge
baryon: protons, neutrons, and other three-quark particles
- particle: very small thing
baryon acoustic oscillations (BAO): density fluctuations stemming from acoustic waves in the early universe
baryon density:
- Lambda-CDM model (ΛCDM,LCDM): Big-Bang cosmological model with a cosmological constant and cold dark matter
Baryon Oscillation Spectroscopic Survey (BOSS): survey of spatial distribution of luminous red galaxies and quasars
- Sloan Digital Sky Survey (SDSS): imaging survey of 500,000,000 objects in 35% of sky
baryonic gas fraction:
- gas fraction: fraction of a galaxy or cluster consisting of gas
baryonic mass density:
- astronomical quantities: some astronomy amounts/numbers
- critical density (ρ_c): density of the universe which leaves it flat
- mass density: density of a volume of space
baryonic matter:
- baryon: protons, neutrons, and other three-quark particles
baryonic Tully-Fisher relation:
- Tully-Fisher relation (TFR): relation between spiral galaxy luminosity and line width
Bas:
- Basel Open Cluster Catalog (Basel): list of open clusters
basalt: an igneous rock type that shows rapid cooling
Basel:
- Basel Open Cluster Catalog (Basel): list of open clusters
Basel Astronomical Institute:
- Basel Open Cluster Catalog (Basel): list of open clusters
Basel Open Cluster Catalog (Basel): list of open clusters
baseline: distance between dishes of an interferometer
- parallax: angle due to different lines of sight
basicity:
- acidity (pH): measure of the activity of hydrogen ions in a solution
basis function: one of a set of functions used to approximate a function of interest
BAT:
- Swift: satellite for studying gamma-ray bursts
BATC: photometric survey of Milky Way stars
bathymetry: study and measurement of sea depths
BATSE:
- Compton Gamma Ray Observatory (CGRO): 1990s space observatory for gamma ray observation
Bayer designation: star designation system dating from 1600s
Bayes' law:
- Bayesian statistics: statistics method assigning probability to your belief
Bayes' rule:
- Bayesian statistics: statistics method assigning probability to your belief
Bayes' theorem:
- Bayesian statistics: statistics method assigning probability to your belief
Bayesian probabilities:
- Bayesian statistics: statistics method assigning probability to your belief
Bayesian statistics: statistics method assigning probability to your belief
- Markov chain Monte Carlo (MCMC): model technique to approximate multi-dimensional integrals
BB:
- black body (BB): idealized object that reflects no light
- CMB polarization: effects of scattering and lensing on the CMB
BBFS:
- HEAO-2: 1978 X-ray observatory space mission
BBG:
- Balmer-break galaxy (BBG): a galaxy emitting very little shorter than 3646 angstroms
BBH:
- black hole binary (BHB,BBH): two black holes co-orbiting
BBN:
- Big Bang nucleosynthesis (BBN): creation of atomic nuclei in the very early universe
BCD:
- dwarf galaxy: small galaxy with a few billion stars
BCE:
- variable star: star that varies in magnitude
BCEP:
- variable star: star that varies in magnitude
BCG:
- brightest cluster galaxy (BCG): a cluster's most luminous galaxy
- dwarf galaxy: small galaxy with a few billion stars
Bcool: project studying stellar magnetism
BCS:
- Yohkoh: 1990s Japanese solar observatory spacecraft
BCVS:
- Bibliographic Catalog of Variable Stars (BCVS): listing of references to variable stars
BD:
- Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
- brown dwarf (BD): star-like object with less mass than a star
- dropout: means of identifying distant galaxies
BD+36 2147:
- Lalande 21185: nearby red dwarf
BDF: field used in search for distant galaxies
BDS:
- Burnham Double Star Catalogue (BDS,BU): 1906 catalog with multiple star systems and non-orbiting double stars
Be:
- Berkeley Open Cluster Catalogue (Be): list of open clusters
Be star: early star with Balmer emission lines
Beagle 2:
- Mars Express: Mars probe launched by ESA in 2003
BearCLAW:
- AstroBEAR: MHD simulation system
Becker, White, and Edwards Catalog (BWE): 1990s radio catalog from a 91m Green Bank Telescope survey
BEFS:
- Berkeley Extreme and Far-UV Spectrometer (BEFS): 1990s UV spectrometer used on two shuttle missions
Beijing-Arizona-Taiwan-Connecticut Survey:
- BATC: photometric survey of Milky Way stars
BEL:
- broad emission line region: region within an AGN with broad emission lines
BEL cloud:
- broad emission line region: region within an AGN with broad emission lines
BEL region:
- broad emission line region: region within an AGN with broad emission lines
bell curve:
- full width at half maximum (FWHM): a measure of the width of a hump-shaped curve
- Gaussian function: function producing the bell curve
- window function: function with a zero value outside some specific range
Bellatrix:
- Orion: well-known constellation in the northern hemisphere
belt:
- superrotating wind: wind traveling in the same direction as the planet is rotating
- zone: apparent "horizontal" band in an atmosphere
Ben:
- rare designator prefixes: designator prefixes generally used for only a few objects
Bennu:
- 101955 Bennu: near-Earth asteroid that is the target of a planned sample-return mission
benzene:
- hydrocarbon (HC): any compound of just carbon and hydrogen
BepiColombo: mission to Mercury
- Mercury: inner-most and smallest planet in the solar system
Berkeley:
- Berkeley Open Cluster Catalogue (Be): list of open clusters
- PAPER: radio interferometer for 21cm measurement
Berkeley Extreme and Far-UV Spectrometer (BEFS): 1990s UV spectrometer used on two shuttle missions
Berkeley Open Cluster Catalogue (Be): list of open clusters
Bernard Lyot Telescope:
- Zeeman-Doppler imaging (ZDI): technique for imaging stellar magnetic fields
Bernstein polynomial: polynomial form capable of producing arbitrary shapes
beryllium:
- triple alpha process: fusion reaction chain turning helium-4 into carbon
Besselian date:
- epoch: when an object was at a particular set of celestial coordinates
Besselian epoch:
- epoch B1950.0: midnight 1/1/1950 GMT as used as a time reference
Besselian year:
- epoch B1950.0: midnight 1/1/1950 GMT as used as a time reference
beta (β): ratio of plasma pressure to magnetic pressure
Beta Canis Majoris star:
- variable star: star that varies in magnitude
Beta Centauri: second brightest star in Centaurus
Beta Cephei variable:
- variable star: star that varies in magnitude
beta decay: radioactivity such that an electron or positron is emitted
beta drift: tendency for a cyclone to drift poleward and westward
Beta Orionis:
- Rigel: brightest star in constellation Orion
beta particle:
- alpha particle: essentially a helium nucleus stemming from radioactivity
- beta decay: radioactivity such that an electron or positron is emitted
- particle spectrometer: device to determine the characteristics of incoming particles
Beta Per:
- Algol (Beta Per,β Per): multiple star system demonstrating affects of mass transfer
Beta Persei:
- Algol (Beta Per,β Per): multiple star system demonstrating affects of mass transfer
Beta Pictoris:
- Beta Pictoris b (β Pic b): super Jupiter discovered in 2008
Beta Pictoris b (β Pic b): super Jupiter discovered in 2008
beta plane:
- Coriolis force: apparent force in a rotating frame of reference
beta ray:
- radioactive heating: a source of heat of some planets and moons
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
BF:
- Voigt profile: mathematical shape that models spectral lines
BG4:
- BlackGEM: telescope array in development to follow up gravitational wave signals
BH:
- black hole (BH): region of such high mass that light cannot escape
- direct collapse black hole (DCBH): theoretical means for quick formation of SMBHs
BH merger:
- black hole merger: two black holes meeting and forming one
BH model:
- black hole model: description of a BH using math or computation
BHAR:
- black hole accretion rate (BHAR): measure, especially used for AGNs
BHB:
- black hole binary (BHB,BBH): two black holes co-orbiting
- blue horizontal branch (BHB): blue end of the horizontal branch
BHXRT:
- transient: observed change in the sky
BHXT:
- transient: observed change in the sky
bias:
- Eddington bias: selection bias from mistaking something common for something rare
- galaxy bias: degree to which galaxy density fails to correspond to dark matter density
- low-surface-brightness galaxy (LSB galaxy): galaxies less bright than those historically identified
- Malmquist bias: selection bias from detecting only the brighter objects
- Scott effect: bias toward finding clusters that have bright galaxies
- volume weighting: method of accommodating the Malmquist bias
Bibliographic Catalog of Variable Stars (BCVS): listing of references to variable stars
bicarbonate:
- acidity (pH): measure of the activity of hydrogen ions in a solution
- carbonate system: system governing water and CO2 in the presence of each other
BICEP:
- BICEP2: survey to measure the polarization of the CMB
BICEP2: survey to measure the polarization of the CMB
BICEP3:
- BICEP2: survey to measure the polarization of the CMB
Big Bang: theoretical event when the universe expanded from a point
- Big Bang nucleosynthesis (BBN): creation of atomic nuclei in the very early universe
- black hole (BH): region of such high mass that light cannot escape
- cosmic time: time since the Big Bang
- cosmology: study of the life of the universe
- dark age: interval when the universe's hydrogen atoms were neutral
- early universe: from the Big Bang to recombination
- epoch of reionization (EOR): time when the universe's neutral hydrogen atoms ionized
- lithium (Li): metal, Li, atomic number 3
- nucleosynthesis: creation of atomic nuclei
- recombination: time when the universe's ionized hydrogen atoms neutralized
Big Bang nucleosynthesis (BBN): creation of atomic nuclei in the very early universe
- nucleosynthesis: creation of atomic nuclei
Big Bang theory:
- Big Bang: theoretical event when the universe expanded from a point
Big Ear:
- Ohio Radio Survey: 1960s radio survey by Ohio State University
BigBOSS: BOSS survey follow-on
BigBOSS Spectrograph:
- BigBOSS: BOSS survey follow-on
Bigelow Sky Survey:
- Catalina Sky Survey (CSS): survey of near-Earth objects
binary:
- binary star: system of two stars co-orbiting
binary asteroid:
- binary minor planet (BMP): minor planet with another body orbiting it
binary black hole:
- black hole binary (BHB,BBH): two black holes co-orbiting
binary burning:
- globular cluster (GC): spherical group of stars orbiting a galaxy
binary minor planet (BMP): minor planet with another body orbiting it
binary neutron star (BNS,NSB): two neutron stars co-orbiting
binary population synthesis:
- stellar population synthesis (SPS): using spectral characteristics of galaxies to characterize their stellar populations
binary SMBH (BSMBH,SMBBH,SMBHB): co-orbiting supermassive black holes
binary star: system of two stars co-orbiting
- Achernar: ninth-brightest star in the sky
- Algol (Beta Per,β Per): multiple star system demonstrating affects of mass transfer
- Alpha Centauri: nearest star system
- Beta Centauri: second brightest star in Centaurus
- Black Widow Pulsar (B1957+20, PSR J1959+2048, PSR B1957+20): binary system consisting of a pulsar and small companion
- DQ Tau: young binary star system
- Epsilon Indi (ε Indi,ε Ind): nearby star system including two brown dwarf companions
- G239-25: nearby red dwarf with brown dwarf companion
- GG Tau: much-studied quadruple star system
- GRO J1655-40: microquasar
- HD 133131: binary star system with exoplanets
- Hulse-Taylor Binary (PSR B1913+16,PSR J1915+1606, PSR 1913+16): binary system consisting of a pulsar and neutron star
- J1713-0747: binary system with millisecond pulsar and white dwarf
- Luhman 16: nearby binary brown dwarf
- Luyten 726-8: nearby binary star system
- Procyon: brightest star in Canis Minor
- Rigel: brightest star in constellation Orion
- Scholz's Star: nearby binary star with red dwarf and brown dwarf
- Sirius: brightest star in the sky
- T Tauri: variable star taken as example of young star
binary star type:
- astrometric binary: binary star system detected by observing the movement of a star
- binary neutron star (BNS,NSB): two neutron stars co-orbiting
- black hole binary (BHB,BBH): two black holes co-orbiting
- 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
- galactic binary: system of two object co-orbiting in the Milky Way
- post-common envelope binary (PCEB): binary star system showing unusual stellar evolution
- 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
- visual binary: binary star system in which both stars can be seen
binary 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
- binary star: system of two stars co-orbiting
- Burnham Double Star Catalogue (BDS,BU): 1906 catalog with multiple star systems and non-orbiting double stars
- Catalogue of Southern Double Stars: 1955 catalog with multiple star systems and non-orbiting double stars
- contact binary: binary stars orbiting so close they are touching
- double star: two stars close together in the sky
- Dunlop Double Star Catalogue (DUN): 1829 catalog of double stars viewed from Australia
- ejection: forcing or throwing something out
- hardness: measure of the binding energy of a binary
- Heggie-Hills law: hard binary stars generally get harder when encountering a third star
- mass function: measure of binaries that constrains the masses
- multiplicity fraction: fraction of star systems that are multiple-star systems
- optical double: two stars that look like one with naked eye
- Rossiter-McLaughlin effect (RM effect,RM): effect of transit on visible spectrum of the star
- stellar population synthesis (SPS): using spectral characteristics of galaxies to characterize their stellar populations
- Struve Catalogs: two catalogs of double stars
- symbiotic binary: giant star transferring mass to a somewhat distant companion
- transit timing variations (TTV): variations in the timing of the transits of exoplanets and binaries
binary supermassive black hole:
- binary SMBH (BSMBH,SMBBH,SMBHB): co-orbiting supermassive black holes
binary system:
- binary star: system of two stars co-orbiting
binary TNO:
- binary minor planet (BMP): minor planet with another body orbiting it
binary trans-Neptune object:
- binary minor planet (BMP): minor planet with another body orbiting it
binary X-ray pulsar:
- pulsar (PSR): astronomical body whose electromagnetic radiation displays a cycle
binary X-ray system:
- binary star: system of two stars co-orbiting
binary YORP:
- Yarkovsky-O'Keefe-Radzievskii-Paddack effect (YORP): rotational effect on asymmetric asteroids
binding energy: energy needed to separate two objects
binomial coefficients:
- Legendre polynomials: useful sequence of polynomials
biofluorescence: common fluorescence in organisms to dissipate harmful UV radiation
- fluorescence: mechanism by which molecules emit a longer wavelength than they absorb
biology:
- astrobiology: study of extra-terrestrial life
- glycine (Gly,G): smallest of the twenty common amino acids
- mass extinction: event in which many species went extinct
- molecular handedness: mirror-imaged variants of some molecules
- water activity (a_w): measure of partial vapor pressure of water
biomarker:
- biosignature: sign of life
biosignature: sign of life
- astrobiology: study of extra-terrestrial life
bipolar outflow: streams of matter from the poles of a protostar
Birkhoff's theorem: shows GR qualities of a spherically-symmetric mass
bispectrum:
- N-point function: general term for analyses-techniques of spatial data
BL Lac object:
- blazar: very compact variable quasar
- Roma-BZCAT: 2013 catalog of blazars
BL Lacertae:
- blazar: very compact variable quasar
black body (BB): idealized object that reflects no light
- Planck function: yields black body curve
- Rayleigh-Jeans law: yields approximation of black body curve
- Wien's displacement law: temperature times wavelength with maximum intensity equals a constant
black body radiation:
- spectral index (α): power by which an object's flux depends on frequency
black body temperature:
- effective temperature (T_eff,Teff): temperature of an equivalent black body in terms of total radiation
black dwarf:
- white dwarf: stellar remnant of mostly electron-degenerate matter
Black Eye Galaxy:
- M64: nearby dusty galaxy
black hole (BH): region of such high mass that light cannot escape
- compact object: dense astronomical body such as white dwarf or denser
- direct collapse black hole (DCBH): theoretical means for quick formation of SMBHs
black hole accretion rate (BHAR): measure, especially used for AGNs
- accretion rate: rate of addition of mass to an object
black hole binary (BHB,BBH): two black holes co-orbiting
black hole merger: two black holes meeting and forming one
black hole model: description of a BH using math or computation
black hole X-ray transient:
- transient: observed change in the sky
black holes:
- accretion: enlargement of an astronomical body by gravitationally attracting additional mass
- accretion disk: disk around an astronomical body of material that is accreting
- advection dominated accretion flow (ADAF): accretion without radiating much energy
- binary SMBH (BSMBH,SMBBH,SMBHB): co-orbiting supermassive black holes
- black hole accretion rate (BHAR): measure, especially used for AGNs
- black hole merger: two black holes meeting and forming one
- black hole model: description of a BH using math or computation
- Blandford-Payne mechanism (BP process): means of extracting BH rotational energy by magnetized accretion disk
- Blandford-Znajek mechanism (BZ process): means of extracting BH rotational energy by magnetized accretion disk
- direct collapse black hole (DCBH): theoretical means for quick formation of SMBHs
- ejection: forcing or throwing something out
- ergosphere: type of region of space around rotating black hole
- event horizon (EH): surface-shape around a black hole through which light cannot escape
- final parsec problem: lack of a convincing theory on how SMBHs can reach each other
- gas streamer: stream of gas
- GRO J1655-40: microquasar
- innermost stable circular orbit (ISCO): border of region surrounding a BH in which orbits are unstable
- jet: stream of matter from an astronomical body
- law of cosmic censorship: a singularity cannot be observed
- microquasar: stellar-sized black hole with quasar-like activity
- retrograde accretion: accretion disk spinning in opposite direction to the body
- Salpeter timescale: timescale for black hole growth
- Schwarzschild radius: radius of a black hole's event horizon
- Soltan argument: distant quasars imply SMBHs still exist
- spacetime diagram: graph of simplified spacetime, with fewer space dimensions
- strong-field gravity: gravity much stronger than in the solar system such as near a black hole
- supermassive black hole (SMBH): black hole with a mass of millions to billions of solar masses
- superradiance: Exotic quantum-mechanics light-amplification phenomenon
- tidal disruption event (TDE,TDF): star pulled apart by black hole tidal forces
- ultraluminous X-ray source (ULX): X-ray source with luminosity between a star and an AGN
Black Widow Pulsar (B1957+20, PSR J1959+2048, PSR B1957+20): binary system consisting of a pulsar and small companion
black-body radiation: continuous spectrum characteristic of the temperature of a body
black-body spectrum:
- black body (BB): idealized object that reflects no light
- black-body radiation: continuous spectrum characteristic of the temperature of a body
- power law: relationship with one quantity a power of another
blackbody:
- black body (BB): idealized object that reflects no light
BlackGEM: telescope array in development to follow up gravitational wave signals
BLAGN:
- Seyfert galaxy: visible active galaxy
Blanco 4m:
- Cerro Tololo Inter-American Observatory (CTIO): observatory near Amado, Arizona
- Deep Lens Survey (DLS): investigating mass distribution of the universe
- NOAO Deep Wide-field Survey (NDWFS): survey investigating large scale structure of the universe
- Supernova Cosmology Project (SCP): used supernova data to determine a history of the universe's expansion
- Víctor M. Blanco Telescope: 4m reflector telescope in Chile
Blandford-Payne mechanism (BP process): means of extracting BH rotational energy by magnetized accretion disk
Blandford-Payne process:
- Blandford-Payne mechanism (BP process): means of extracting BH rotational energy by magnetized accretion disk
Blandford-Znajek mechanism (BZ process): means of extracting BH rotational energy by magnetized accretion disk
Blandford-Znajek process:
- Blandford-Znajek mechanism (BZ process): 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 1.8m submillimeter telescope
BLAST-TNG:
- BLAST: balloon-borne 1.8m submillimeter telescope
BLASTPol:
- BLAST: balloon-borne 1.8m submillimeter telescope
blazar: very compact variable quasar
- 3C 273: first quasar discovered
- Roma-BZCAT: 2013 catalog of blazars
blaze angle:
- grating: spectrometer component
blazed grating:
- grating: spectrometer component
blend analysis:
- blended spectra: an observed spectrum comprising light from multiple objects
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
blind survey: survey conducted independently of prior information
BLL:
- blazar: very compact variable quasar
BLLAC:
- blazar: very compact variable quasar
blow off:
- atmospheric escape: escape of gas particles from a planet's atmosphere
blowoff:
- hydrodynamic escape: ongoing escape of gas particles from atmosphere
BLR:
- Seyfert galaxy: visible active galaxy
blue:
- B: photometric filter for blue light
blue compact dwarf galaxy:
- dwarf galaxy: small galaxy with a few billion stars
blue compact galaxy:
- dwarf galaxy: small galaxy with a few billion stars
blue dropout galaxy:
- dropout: means of identifying distant galaxies
blue galaxy:
- galaxy: gravitationally-bound group of stars
- galaxy main sequence: relation between galaxies' star formation and stellar mass
blue giant:
- asymptotic giant branch (AGB): a second stage of helium burning in some stars
- giant star: star larger than main sequence stars
- red giant: very bright red star
blue horizontal branch (BHB): blue end of the horizontal branch
blue noise:
- red noise: noise tending toward lower frequencies
blue shift:
- data cube: "table" of numerical data covering three dimensions
- line broadening: processes causing a spectral line to have width
- redshift (z): change to longer wavelengths due to Doppler affects
blue straggler:
- open cluster: group of stars within a galaxy apparently formed by a single cloud
- turn-off point (TO): point in H-R diagram of a cluster where stars turn red
blue supergiant:
- supergiant: very large giant star
BMBF:
- Astronet: European astronomy consortium
BMP:
- binary minor planet (BMP): minor planet with another body orbiting it
BNS:
- binary neutron star (BNS,NSB): two neutron stars co-orbiting
Bode designation:
- Flamsteed designation: star designation system dating from 1700s
Bode's law:
- Titius-Bode law: relationship between the distances between solar system planets
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:
- Bohr model: has electrons circling nucleus in quantized orbits
boil off:
- Jeans escape: ongoing escape of gas particles from atmosphere
boiling point:
- refractory material: material with high condensation temperature
- volatile material: material with low condensation temperature
Bok globule: dense molecular cloud
Bol'shoi Teleskop Azimultal'nyi:
- Large Altazimuth Telescope (BTA-6): 6 meter reflector telescope in Russia
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 30m telescope
- MUSTANG: bolometer array on the Green Bank Telescope
- SCUBA: submillimeter instrument on James Clark Maxwell Telescope
bolometric:
- bolometer: instrument measuring heat produced by radiation
bolometric correction: difference between an object's bolometric and visible magnitudes
bolometric luminosity (L_Bol): total luminosity of an object at all wavelengths
bolometric magnitude (Mbol,M_bol): absolute magnitude of all wavelengths
Bolshoi simulation: cosmological simulation
Boltzmann constant (k,k_B): relates particle energy and temperature
Boltzmann distribution:
- Boltzmann equation: equation relating atomic excitation to temperature
Boltzmann equation: equation relating atomic excitation to temperature
- stellar dynamics: stars' gravitational interaction
Boltzmann factor:
- Boltzmann equation: equation relating atomic excitation to temperature
- partition function (Z): scale factor for Boltzmann factors
Boltzmann relation:
- Boltzmann equation: equation relating atomic excitation to temperature
bond:
- hydrocarbon (HC): any compound of just carbon and hydrogen
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
bone:
- filament: linear volume of high molecular gas density within a galaxy
Bonner Durchmusterung Catalog (BD): well-known astrometric catalog from late 1800s
BOOMERanG: 1990s-2000s balloon-borne 1.3 meter millimeter telescope
born again star:
- asymptotic giant branch (AGB): a second stage of helium burning in some stars
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:
- Bose-Einstein statistics: possible distribution of particles not bound by Pauli exclusion
- electron degeneracy: the condition of electrons supported solely by the Pauli exclusion principle
- pair production: creation of a particle/antiparticle pair
- particle: very small thing
- Pauli exclusion principle: fermions in a quantum system cannot have identical quantum numbers
- photon: quantum of light, i.e., light as a particle
- spin (m_s): an angular-momentum quantum number
BOSS:
- Baryon Oscillation Spectroscopic Survey (BOSS): survey of spatial distribution of luminous red galaxies and quasars
BOSS Spectrograph:
- Sloan 2.5m Telescope: telescope for SDSS in New Mexico
bottom quark:
- particle: very small thing
- standard model: model of elementary particles including quarks
bouncing barrier: the problem that the seeds of planets would rebound rather than merge
- barrier: challenging issue regarding planet formation
- meter size barrier: a barrier to planet formation on the order of a meter diameter
bound GMC:
- giant molecular cloud (GMC): interstellar gas cloud with molecules, thousands of solar masses
bound-bound:
- absorption: removal of photons from a beam of EMR
- atomic excitation: atoms with electrons above the ground state
bound-free:
- absorption: removal of photons from a beam of EMR
- Kramers opacity law: opacity's relation to density and temperature
- photoionization: photon striking neutral atom expelling an electron
boundary condition:
- stellar structure: the presumed internal structure of stars
bow shock: shock wave of a magnetosphere through the surrounding medium
Boyajian's Star:
- KIC 8462852: star with unusual variations
Boyle's law:
- equation of state (EoS): equation relating temperature, pressure, and volume
- statistical mechanics: mechanical behavior based upon probability
BP process:
- Blandford-Payne mechanism (BP process): means of extracting BH rotational energy by magnetized accretion disk
Bp star:
- Ap star: peculiar type of A star
BP/RP:
- Gaia: survey satellite at 400-1000 nanometers
BPM:
- Bruce Proper Motion Survey (BPM): 1941 southern-hemisphere survey catalog of Luyten's
BPS:
- stellar population synthesis (SPS): using spectral characteristics of galaxies to characterize their stellar populations
BR:
- rare designator prefixes: designator prefixes generally used for only a few objects
bracket notation:
- metallicity (Z): metal fraction of an object
Brackett:
- Brackett series: hydrogen lines for electrons settling from n > 4 to n = 4
Brackett series: hydrogen lines for electrons settling from n > 4 to n = 4
break-up velocity:
- stellar rotation: the angular motion of a star around its axis
breaking a degeneracy:
- degeneracy: general word meaning a violation of normal rules
breaking atmospheric wave:
- internal gravity wave: ripples in a change in density in a fluid
breaking radiation:
- bremsstrahlung: photon emission when a charged particle is decelerated
Breakthrough Starshot:
- Starshot: plan for mission to fly by Alpha Centauri
bremsstrahlung: photon emission when a charged particle is decelerated
- electron scattering: any process that changes the course of an electron
- spectral index (α): power by which an object's flux depends on frequency
BRI:
- rare designator prefixes: designator prefixes generally used for only a few objects
bright giant:
- giant star: star larger than main sequence stars
- luminosity class: classification of size/luminosity of stars
- supergiant: very large giant star
bright nebula:
- cloud: higher-density region of space
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
- 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 (HR,BS,YBS): early 20th century catalog of 9000 stars
bright supergiant:
- supergiant: very large giant star
brightest cluster galaxy (BCG): a cluster's most luminous galaxy
brightest star:
- planetary nebula luminosity function (PNLF): model used in distance estimation
brightness:
- AB system: monochromatic magnitude calibration based upon absolute values
- absolute magnitude (M): magnitude as seen from 10 parsecs
- apparent magnitude (m): magnitude as seen from Earth adjusted for Earth atmosphere
- bolometric magnitude (Mbol,M_bol): absolute magnitude of all wavelengths
- K correction: correction to magnitude for redshift
- magnitude: a logarithmic measure of brightness
- Vega system: magnitude calibration such that Vega has zero magnitude
British Columbia:
- Canadian Hydrogen Intensity Mapping Experiment (CHIME): radio telescope mapping distant neutral hydrogen
- Dominion Observatory 10.03 MHz Source Catalog (DB): 1960s survey of northern-hemisphere radio sources
- Dominion Observatory 1420 MHz Source Catalog (DA): 1960s survey of northern-hemisphere radio sources
- Dominion Radio Astrophysical Observatory (DRAO): radio observatory in British Columbia, Canada
- Large Zenith Telescope (LZT): 6 meter liquid mirror telescope in British Columbia
broad band photometry:
- photometry: studying starlight through bandpass filters
broad emission line cloud:
- broad emission line region: region within an AGN with broad emission lines
broad emission line region: region within an AGN with broad emission lines
broad line AGN:
- Seyfert galaxy: visible active galaxy
broad line region:
- Seyfert galaxy: visible active galaxy
broadband:
- bandwidth: number of hertz between minimum and maximum frequencies
broadening:
- line broadening: processes causing a spectral line to have width
broadening function:
- Voigt profile: mathematical shape that models spectral lines
brown dwarf (BD): star-like object with less mass than a star
- Epsilon Indi (ε Indi,ε Ind): nearby star system including two brown dwarf companions
- Luhman 16: nearby binary brown dwarf
- Scholz's Star: nearby binary star with red dwarf and brown dwarf
- substellar object: star-like object with less mass than a star
- WISE 0855-0714: nearby brown dwarf
- WISE 1506+7027: nearby brown dwarf
brown dwarfs:
- CFBDS: survey in search of brown dwarfs
- CTIO Upper-Scorpius OB Association Survey (UScoCTIO): survey of low-mass stars and 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
BrsO:
- rare designator prefixes: designator prefixes generally used for only a few objects
Bruce Proper Motion Survey (BPM): 1941 southern-hemisphere survey catalog of Luyten's
Brunt-Väisälä frequency: natural frequency of buoyancy waves
brute force:
- finite difference method (FDM): means of estimating calculus and differential equation solutions
BS:
- Bright Star Catalog (HR,BS,YBS): early 20th century catalog of 9000 stars
- open cluster: group of stars within a galaxy apparently formed by a single cloud
- turn-off point (TO): point in H-R diagram of a cluster where stars turn red
BSE:
- bulk silicate earth (BSE): the early overall composition of the silicate part of Earth
BSG:
- supergiant: very large giant star
BSMBH:
- binary SMBH (BSMBH,SMBBH,SMBHB): co-orbiting supermassive black holes
BSO:
- rare designator prefixes: designator prefixes generally used for only a few objects
BSS:
- Catalina Sky Survey (CSS): survey of near-Earth objects
- open cluster: group of stars within a galaxy apparently formed by a single cloud
- turn-off point (TO): point in H-R diagram of a cluster where stars turn red
BT-Settl: model atmosphere of small stars and brown dwarfs
BTA-6:
- Large Altazimuth Telescope (BTA-6): 6 meter reflector telescope in Russia
BTFR:
- Tully-Fisher relation (TFR): relation between spiral galaxy luminosity and line width
BU:
- Burnham Double Star Catalogue (BDS,BU): 1906 catalog with multiple star systems and non-orbiting double stars
buckminsterfullerene:
- diffuse interstellar bands (DIBs): type of absorption bands seen in astronomical objects
- polycyclic aromatic hydrocarbon (PAH): hydrocarbons consisting of meshes of benzene rings
bucky ball:
- polycyclic aromatic hydrocarbon (PAH): hydrocarbons consisting of meshes of benzene rings
bulge: denser group of stars within a larger group
bulk atmosphere:
- atmosphere: gas surrounding astronomical object
bulk density: total mass divided by total volume
bulk metallicity:
- metallicity (Z): metal fraction of an object
bulk modulus:
- sound speed: speed at which compression waves traverse a gas
bulk planetary atmosphere:
- atmosphere: gas surrounding astronomical object
bulk silicate earth (BSE): the early overall composition of the silicate part of Earth
Bullet Cluster: example of two galaxy clusters in collision
buoyancy frequency:
- Brunt-Väisälä frequency: natural frequency of buoyancy waves
Burnham:
- Burnham Double Star Catalogue (BDS,BU): 1906 catalog with multiple star systems and non-orbiting double stars
Burnham Double Star Catalogue (BDS,BU): 1906 catalog with multiple star systems and non-orbiting double stars
burning:
- fusion: formation of an atomic nucleus nuclei from multiple smaller nuclei
burst:
- gravitational-wave memory: a gravitational wave that does not return
burst gravitational wave:
- gravitational-wave memory: a gravitational wave that does not return
BWE:
- Becker, White, and Edwards Catalog (BWE): 1990s radio catalog from a 91m Green Bank Telescope survey
BY:
- variable star: star that varies in magnitude
BY Draconis star:
- variable star: star that varies in magnitude
BY Draconis variable:
- variable star: star that varies in magnitude
BYORP:
- Yarkovsky-O'Keefe-Radzievskii-Paddack effect (YORP): rotational effect on asymmetric asteroids
Byurakan Observatory:
- Second Byurakan Survey (SBS): 1970s-1990s survey of galaxies and quasars
BZ:
- Roma-BZCAT: 2013 catalog of blazars
BZ process:
- Blandford-Znajek mechanism (BZ process): means of extracting BH rotational energy by magnetized accretion disk

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