Term Index (T)
Astrophysical terms and names of things beginning with the letter T.
T2
T4
TA
TB
TC
TD
TE
TF
TG
TH
TI
TJ
TK
TL
TM
TN
TO
TP
TR
TS
TT
TU
TV
TW
TX
TY
TZ
- T (T-type star): brown dwarf with a temperature in the vicinity of 1000 K
- T (tesla): unit of magnetic flux density
- t (timescale): general length of time something takes
- T association: stellar association with T-Tauri stars
- T dwarf (T-type star): brown dwarf with a temperature in the vicinity of 1000 K
- brown dwarf: star-like object with less mass than a star
- T Pyx (T Pyxidis): well-known recurrent nova
- T Pyxidis: well-known recurrent nova
- T Tau (T Tauri): variable star taken as example of young star
- T Tau N
- T Tauri: variable star taken as example of young star
- T Tau Sa
- T Tauri: variable star taken as example of young star
- T Tau Sb
- T Tauri: variable star taken as example of young star
- T Tauri: variable star taken as example of young star
- Télescope à Action Rapide pour les Objets Transitoires (TAROT): network of telescopes to catch GRB optical counterparts
- TŻO (Thorne-Żytkow object): giant star with a neutron star at its center
- T-1: see Palomar-Leiden Survey
- T-2: see Palomar-Leiden Survey
- T-3: see Palomar-Leiden Survey
- T-class: see T-type star
- T-class star (T-type star): brown dwarf with a temperature in the vicinity of 1000 K
- T-mode: see CMB polarization
- T-ReCS: see Gemini Observatory
- T-Tauri star: type of variable pre-main-sequence star
- T-type star: brown dwarf with a temperature in the vicinity of 1000 K
- T2CAM: see Lucy
- T4 APT (T4 Automated Photometric Telescope): automated 75-cm telescope to a long-term star monitoring survey
- T4 Automated Photometric Telescope: automated 75-cm telescope to a long-term star monitoring survey
- t0: see Lambda-CDM model
- t0: see seeing
- TB (brightness temperature): temperature of an equivalent black body in terms of spectral radiance
- TBB (effective temperature): temperature of an equivalent black body in terms of total radiation
- TC (color temperature): temperature-measure of a source based on a color index
- Te (elastic thickness): measure of the thickness of a sagging layer of a planet surface
- Teff (effective temperature): temperature of an equivalent black body in terms of total radiation
- Teph
- time standard: method of designating points in time and quantifying time periods
- Teq (equilibrium temperature): temperature a planet would have if it were an externally-heated black body
- tH (Hubble time): approximation of the age of the universe
- Tn: see elastic thickness
- TVir: see virial theorem
- TA (Telescope Array Project): cosmic-ray observatory aiming for extremely energetic particles
- Tabby's Star (KIC 8462852): star with unusual variations
- Table Mountain Facility (Table Mountain Observatory): NASA observatory near Los Angeles
- Table Mountain Observatory: NASA observatory near Los Angeles
- TAC: telescope allocation committee
- TAC: time allocation committee (for telescopes)
- TAC 1.0: see USNO Twin Astrograph
- TAC 2.0: see USNO Twin Astrograph
- tadpole orbit
- halo orbit: type of orbit around an unstable Lagrangian point
- TAI: see Terrestrial Time
- TAIGA experiment (Tunka experiment): Russian Cherenkov detector aimed at cosmic rays and gamma rays
- tail: see comet
- TAIPAN: multi-object spectrograph with robot fiber-positioner
- TAIPAN: see UK Schmidt Telescope
- Taipan Galaxy Survey
- TAIPAN: multi-object spectrograph with robot fiber-positioner
- Taiwan
- TALE: see Telescope Array Project
- TAM: non-gray-RT 3D model of Titan's atmosphere
- TAMA 300: small prototype gravitational wave detector in Japan
- TAMBO: concept for neutrino detector in valley in Peru
- TAMS: see zero-age main sequence
- Tamura: see rare designator prefixes
- tangential velocity: see radial velocity
- TAO (University of Tokyo Atacama Observatory): observatory for a 6.5 m infrared telescope under construction
- TAP: see Taurus-Auriga Complex
- TAR (traditional approximation of rotation): approximation of waves on a rotating body
- TARA: see Telescope Array Project
- Tarantula Nebula (30 Doradus): HI region in LMC
- TAROT: network of telescopes to catch GRB optical counterparts
- TAROT telescope
- task
- task-based parallelism: breaking a computation into tasks that can be run in parallel
- TASS (The Amateur Sky Survey): amateur comet and variable-star search survey
- TASV: see rare designator prefixes
- Tata Institute of Fundamental Research - India: Indian math and science research institute
- TAU (Thousand Astronomical Units): 1980s plan for space probe to travel 1000 AU over 50 years
- Tau: see Tau-REx
- tau: see lepton
- standard model: model of elementary particles including quarks
- supersymmetry: extension to standard model of particle physics
- TAMBO: concept for neutrino detector in valley in Peru
- tau neutrino: neutrino flavor that becomes a tau particle during interactions
- Tau Air Shower Mountain-Based Observatory (TAMBO): concept for neutrino detector in valley in Peru
- tau neutrino: neutrino flavor that becomes a tau particle during interactions
- Tau Retrieval for Exoplanets (Tau-REx): spectral line retrieval code for exoplanet atmospheres
- Tau-Aur Complex (Taurus-Auriga Complex): nearby star-forming region
- Tau-REx: spectral line retrieval code for exoplanet atmospheres
- Taub spacetime: early 1950s model for a rotating-black-hole spacetime
- Taub-NUT metric: see Taub-NUT spacetime
- Taub-NUT spacetime: early mathematics for a rotating black hole spacetime
- Tauras A (Crab Nebula): supernova remnant in Taurus
- Taurus Auriga Perseus Complex: see Taurus-Auriga Complex
- Taurus Dark Clouds (Taurus-Auriga Complex): nearby star-forming region
- Taurus Molecular Cloud (Taurus Molecular Cloud 1): nearby star-forming region
- HL Tau: much-studied T-Tauri star
- Taurus Molecular Cloud 1: nearby star-forming region
- Taurus Molecular Cloud 2: see Taurus Molecular Cloud 1
- Taurus Molecular Cloud 2: see Taurus-Auriga Complex
- Taurus: balloon-borne polarimeter to study the CMB
- TAURUS-1: see Isaac Newton Telescope
- Taurus-Auriga Complex: nearby star-forming region
- Taurus-Auriga Region (Taurus-Auriga Complex): nearby star-forming region
- Taurus-Auriga SFR (Taurus-Auriga Complex): nearby star-forming region
- Taurus-Auriga T association
- TAUVEX: see Spektr-RG
- TAV: see rare designator prefixes
- Taylor column: see Taylor-Proudman theorem
- Taylor series
- Taylor series expansion
- Taylor-Proudman theorem: theorem regarding movement through a rotating fluid
- TB: see CMB polarization
- TBHD: see rare designator prefixes
- TBJ: see rare designator prefixes
- TBL
- TBP (task-based parallelism): breaking a computation into tasks that can be run in parallel
- TBTF: see dwarf galaxy problem
- TC: see SELENE
- Tc: see technetium star
- Tc-rich star (technetium star): star showing technetium absorption lines
- TCB: see time standard
- TCG: see Terrestrial Time
- TCP: see rare designator prefixes
- TCS: see Teide Observatory
- TD: see neutron star merger
- time standard: method of designating points in time and quantifying time periods
- TD-1 (TD-1A): 1970s European observatory-satellite with UV telescopes
- TD-1A: 1970s European observatory-satellite with UV telescopes
- TD1: see TD-1A
- TDB: see time standard
- TDE (tidal disruption event): star pulled apart by black hole tidal forces
- TDF (tidal disruption event): star pulled apart by black hole tidal forces
- TDRSS (Tracking and Data Relay Satellite System): NASA satellites used for communication and tracking of space probes
- TDT
- time standard: method of designating points in time and quantifying time periods
- TDV: see transit timing variations
- TE (thermodynamic equilibrium): state of a system with no net heat flows
- TE: see CMB polarization
- technetium: see technetium star
- technetium star: star showing technetium absorption lines
- technique
- technology
- technomarker (technosignature): sign of technology
- technosignature: sign of technology
- TECP: see Phoenix
- tectonic activity: see crustal plates
- TEDI: see TripleSpec
- Teegarden's Star: nearby red dwarf
- Teff (effective temperature): temperature of an equivalent black body in terms of total radiation
- TEGA: see Mars Polar Lander
- TEGA: see Phoenix
- Teide: see rare designator prefixes
- Teide Observatory: observatory on Mount Teide in the Canary Islands
- telegrapher's equations: two equations describing a transmission line
- telescope: instrument to observe at a distance
- Telescope Array Experiment (Telescope Array Project): cosmic-ray observatory aiming for extremely energetic particles
- Telescope Array Low Energy extension: see Telescope Array Project
- Telescope Array Project: cosmic-ray observatory aiming for extremely energetic particles
- Telescope Array RADAR: see Telescope Array Project
- Telescope Nazionale Galileo
- HARPS-N: high-precision spectrograph for exoplanet searches in Canary Islands
- telescope nut: avid amateur telescope maker self-description
- telescope operator: professional technical position at a research telescope site
- telescope type: term indicating band or optics of a telescope
- telescopes
- Telescopes in Education: program giving grade-school students access to robotic telescopes
- telescopic asterism: see asterism
- Telescopio Carlos Sanchez: see Teide Observatory
- Telescopio Nazionale Galileo: 3.58 m telescope in Canary Islands
- telluric (telluric star): star of known spectrum used for calibration
- telluric contamination: see telluric line
- telluric correction: see telluric line
- telluric line: absorption line in ground observation due to Earth atmosphere
- telluric line subtraction: see telluric line
- telluric planet (rocky planet): planet like Earth and Mars, mostly rock
- telluric standard star (telluric star): star of known spectrum used for calibration
- telluric star: star of known spectrum used for calibration
- telluric line: absorption line in ground observation due to Earth atmosphere
- tellurium
- CUORE: experiment to sense neutrinoless double beta decay
- Tempel 1
- Deep Impact: mission to create and observe an impact with a comet
- EPOXI: mission using Deep Impact for further exploration
- Stardust: space mission that collected and returned comet coma dust
- temperature: measure of hotness/coldness of matter
- temperature gradient
- temperature inversion: see atmospheric temperature profile
- temperature profile (atmospheric temperature profile): the atmosphere's temperature by altitude
- temperature scale height: see scale height
- templates: mechanism to help classify many survey objects or events
- Tempo
- Tempo2
- temps dynamique barycentrique: see time standard
- temps-coordonnée barycentrique: see time standard
- Tenagra observatory
- Tenerife
- Tenerife Experiment: 1980s-1990s survey of CMB anisotropies
- TENGOO: see MMX
- tensor
- TEP (Transits of Extrasolar Planets): late 1990s search for transiting planets
- Teq (equilibrium temperature): temperature a planet would have if it were an externally-heated black body
- terahertz
- Terahertz Intensity Mapper (TIM): planned balloon-borne 2 m telescope and spectrometer
- terminal-age main sequence: see zero-age main sequence
- termination shock: see heliosheath
- terminator: line between regions of day and night
- terminology
- abiotic: produced by something other than life
- basal: from the base or from below
- celestial: having to do with stars and the sky
- coalescence: merging together, becoming one thing
- crowd-sourcing: carrying out large efforts by combining that of many volunteers
- cryogenic: colder than 120 kelvins
- dex: a number or ratio's log base 10
- diagnostic: test or measurement that reveals something's characteristics
- ejecta: material ejected from something
- fusor: 2003 proposed term for astronomical objects capable of carrying out fusion
- in situ: on site
- inspiral: like an orbit that is growing smaller
- microsatellite: NASA term for a 10-100 kg small satellite
- morphology: form and structure
- nanosatellite: NASA term for a 1-10 kg small satellite
- small satellite: NASA term for a satellite of 1200 kg or less
- smoking gun: convincing piece of evidence
- Terra Hunting Experiment: search for exoplanets using HARPS3
- terrestrial dynamical time
- time standard: method of designating points in time and quantifying time periods
- terrestrial gamma-ray flash: gamma rays emitted from Earth lightning storms
- terrestrial planet (rocky planet): planet like Earth and Mars, mostly rock
- Terrestrial Planet Finder: plan for space telescopes to find smaller exoplanets
- Terrestrial Time: current measure of time for astronomical observations on Earth
- terrestrial time: see time standard
- tertiary mirror: see primary mirror
- Terz: see rare designator prefixes
- Terzan: see rare designator prefixes
- TES (transition edge sensor): sensor using superconductivity's strong temperature sensitivity
- TES: see Mars Global Surveyor
- TES: see Mars Observer
- TES bolometer: see transition edge sensor
- TES Camera: see Atacama Submillimeter Telescope Experiment
- TESCAM: see Atacama Submillimeter Telescope Experiment
- tesla: unit of magnetic flux density
- TESS (Transiting Exoplanet Survey Satellite): observatory-satellite searching for transiting exoplanets
- TESS Duo: see Transiting Exoplanet Survey Satellite
- TESS Follow-up Observing Program: see Transiting Exoplanet Survey Satellite
- TESS input catalog: see Transiting Exoplanet Survey Satellite
- TESS object of interest: see Transiting Exoplanet Survey Satellite
- TESS-bis: see Transiting Exoplanet Survey Satellite
- TESS-Keck Survey: Keck follow-up survey to TESS discoveries
- Tethys: see Saturn
- moon: a planet's natural satellite, such as Earth's
- tetrahedron
- Teutsch: see rare designator prefixes
- Texas
- Texas Interferometer: see Texas Survey of Radio Sources at 365 MHz
- Texas Supernova Search: see supernova survey
- Texas Survey of Radio Sources at 365 MHz: 1970s/1980s radio survey made with the Texas Interferometer
- TEXES: see Gemini Observatory
- texture: see topological defect
- TFOP: see Transiting Exoplanet Survey Satellite
- TFR (Tully-Fisher relation): relation between spiral galaxy luminosity and line width
- TGE
- TGF (terrestrial gamma-ray flash): gamma rays emitted from Earth lightning storms
- TGI: see QUIJOTE
- TGO (Trace Gas Orbiter): ESA and Russian Mars orbiter-probe launched in 2016
- TGSS: see Giant Metrewave Radio Telescope
- TGU: see rare designator prefixes
- Th: see rare designator prefixes
- THA (Tucana Horologium association): nearby stellar association
- THA: see rare designator prefixes
- THA star: see Tucana Horologium association
- THE (Terra Hunting Experiment): search for exoplanets using HARPS3
- The Accident (WISE 1534-1043): nearby brown dwarf with high proper motion
- The Amateur Sky Survey: amateur comet and variable-star search survey
- The Anvil of Creation: see STARFORGE
- The Arecibo Legacy Fast ALFA Survey (ALFALFA): HI survey of many galaxies
- The B-Star Exoplanet Abundance Study (BEAST): survey of B stars for possible exoplanets
- The Colossus Telescope (Colossus Telescope): concept for a 50-meter telescope using interferometry
- The H2O Southern Galactic Plane Survey: survey of molecular clouds in the galactic plane
- The LaSilla-QUEST Variability Survey
- QUEST: sixteen square-degree survey camera
- The Near Earth Space Surveillance Initiative: collaboration to survey NEOs
- The PLUTO-Cloudy Interface: see Cloudy
- The Survey for Ionization in Neutral Gas Galaxies: survey of HI in galaxies found through the H-alpha line
- The Univese in Words (El Universo en palabras): Series of audios produced by Astroaccesible
- Theano: see PyMC
- Theia: see Moon formation
- THEMIS: set of satellites studying the Earth's magnetic field
- THEMIS: see Mars Odyssey
- Themis
- theoretical modified GR metric: metric devised to define modifications to GR
- theory
- theory of equilibrium figures (theory of figures): type of model relating a planet's shape to its rotation
- Theory of Everything: single law explaining the four forces of nature
- symmetry breaking: loss of symmetry, such as due to loss of stability in a regime change
- theory of figures: type of model relating a planet's shape to its rotation
- theory of figures of planets rotating in hydrostatic equilibrium (theory of figures): type of model relating a planet's shape to its rotation
- thermal bremsstrahlung: type of EMR produced by thin, hot plasma
- thermal broadening (Doppler broadening): broadening of spectral lines due to movement of the sources of photons
- thermal diffusivity
- Rayleigh number: measure reflecting a fluid system's propensity to convection
- thermal Doppler broadening (Doppler broadening): broadening of spectral lines due to movement of the sources of photons
- thermal dust emission: glow of dust heated by stars or AGNs
- thermal emission: EMR due to a body's heat
- thermal energy: see kinetic energy
- thermal equilibrium: state of a system with no net heat flows
- thermal escape: see atmospheric escape
- thermal inertia: a measure of a material's ability to absorb heat through conduction
- thermal infrared: infrared emission due to black body radiation
- thermal inversion: see atmospheric temperature profile
- thermal IR: see infrared
- thermal KID: see KID
- thermal noise: noise inherent in electronic component warmer than absolute zero
- photon noise: variation in light measurement due to its quantum nature
- thermal phase curve: see phase curve
- thermal pulse: pulse in an AGB star due to helium fusion in a shell
- thermal pulse AGB: see asymptotic giant branch
- thermal pulse cycle: see thermal pulse
- thermal radiation (thermal emission): EMR due to a body's heat
- black-body radiation: EMR with a characteristic spectrum due to the temperature of a body
- emissivity: measure of a material's efficiency at radiating thermal radiation
- thermal runaway: situation where heat triggers more heat production
- thermal Sunyaev-Zel'dovich effect: see Sunyaev-Zel'dovich effect
- thermal tide: see atmospheric tide
- thermal timescale (Kelvin-Helmholtz timescale): time that would radiate away a body's heat energy given its luminosity
- thermal timescale: see timescale
- thermal Urca process: see Urca process
- thermal wind: type of wind due to temperature gradients that vary by altitude
- thermal wind balance: see thermal wind
- thermodynamic equilibrium: state of a system with no net heat flows
- thermodynamics: physics of heat and energy
- thermoelectric effect: see MMRTG
- thermonuclear supernova (Type Ia supernova): type of supernova for which distance can be determined
- supernova: stellar explosion larger than a nova
- thermosphere: see atmospheric temperature profile
- ionosphere: layers of Earth atmosphere with significant ions
- Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED): space probe observing Earth upper atmosphere for solar effects
- THESEUS: plan for X-ray/Gamma-ray transient space mission
- Theta 1 Orionis (Trapezium Cluster): open cluster of stars in Orion Nebula
- Theta1 Orionis (Trapezium Cluster): open cluster of stars in Orion Nebula
- thick disk: disk-shaped set of older stars within the Milky Way
- thick disk: see disk galaxy
- thick disk stars: see disk galaxy
- thick shell: see Europa
- thin disk: disk-shaped set of younger stars within the Milky Way
- thin disk (alpha disk): well-known model of an accretion disk
- thin disk: see disk galaxy
- thin disk accretion: see alpha disk
- thin disk stars: see disk galaxy
- thin shell: see Europa
- Third Cambridge Catalogue of Radio Sources: 1959 catalog of northern hemisphere 159-MHz sources
- Third Catalogue of Nearby Stars (Gliese-Jahreiss Catalog): 1991 catalog of stars within 25 parsecs
- third dredge-up: see dredge-up
- Third Reference Catalogue of Bright Galaxies: see Reference Catalogue of Bright Galaxies
- third-order coma
- third-order TOF: see theory of figures
- Thirty Meter Telescope: extremely large telescope planned for Hawaii
- Thomson optical depth: a measure of effects of Thomson scattering
- Thomson scattering: elastic scattering of photons by a charged particle
- Thomson scattering optical depth (Thomson optical depth): a measure of effects of Thomson scattering
- Thomson thick: see Thomson optical depth
- THOR: see ADAM::THOR
- Thor-Delta 1A (TD-1A): 1970s European observatory-satellite with UV telescopes
- thorium
- Thorne-Żytkow object: giant star with a neutron star at its center
- Thousand Astronomical Units: 1980s plan for space probe to travel 1000 AU over 50 years
- three dimensional model: computer simulation handling variation in all three dimensions
- three mirror anastigmat
- three-body capture: see tidal capture
- three-body problem: see N-body problem
- three-mirror anastigmat: general type of reflector telescope
- Thuan-Gunn photometric system (griz photometric system): photometric system designed for electronic sensors
- Ti (titanium): metal, Ti, atomic number 22
- Tiangong space station: Chinese manned space laboratory under construction in space
- Tianlai (Tianlai Project): 21-cm line intensity mapping project
- Tianlai Cylinder Array: see Tianlai Project
- Tianlai Dish Array: see Tianlai Project
- Tianlai Experiment (Tianlai Project): 21-cm line intensity mapping project
- Tianlai Project: 21-cm line intensity mapping project
- TianQin: proposed Chinese space mission to detect gravitational waves
- Tianwen-1: active Chinese Mars rover/orbiter mission
- Tianyan (FAST): Arecibo-like 500 m telescope in China
- Tibet
- TIC: see Hipparcos
- TIC: see Transiting Exoplanet Survey Satellite
- TICCE: see EURECA
- tidal
- galactic tide: effect of one galaxy's gravity, such as on another galaxy
- Love number: measures of rigidity of a body
- Roche limit: nearest a body can orbit another and survive
- tidal arm: arm of gas and potentially stars leading from a galaxy
- tidal disruption event: star pulled apart by black hole tidal forces
- tidal force: effect of a third body on the gravitational force between two bodies
- tidal heating: heating due to friction from motions caused by tidal force
- tidal locking: locked rotation of an orbiting body
- tidal migration: interaction between tide and orbiting body that changes the orbit
- tidal Q: measure of orbital energy dissipated per orbit due to tidal forces
- tidal tail: string of mass ejected by a tidal forces in a neutron star merger
- tidal acceleration: see tidal force
- tidal migration: interaction between tide and orbiting body that changes the orbit
- tidal arm: arm of gas and potentially stars leading from a galaxy
- tidal braking: see tidal force
- tidal capture: bodies entering orbit through dissipation of energy by tides
- tidal deceleration: see tidal force
- tidal deformability: see neutron star merger
- tidal deformability parameter: see neutron star merger
- tidal disruption event: star pulled apart by black hole tidal forces
- tidal disruption flare (tidal disruption event): star pulled apart by black hole tidal forces
- tidal disruption radius: see Hill radius
- tidal dissipation function: see tidal Q
- tidal equilibrium: see tidal force
- tidal flexing (tidal heating): heating due to friction from motions caused by tidal force
- tidal force: effect of a third body on the gravitational force between two bodies
- tidal heating: heating due to friction from motions caused by tidal force
- tidal locking: locked rotation of an orbiting body
- tidal migration: interaction between tide and orbiting body that changes the orbit
- tidal parameter: see neutron star merger
- tidal period: see tidal Q
- tidal plume: see tidal tail
- tidal potential: see tide
- tidal Q: measure of orbital energy dissipated per orbit due to tidal forces
- tidal Q factor (tidal Q): measure of orbital energy dissipated per orbit due to tidal forces
- tidal Q factor: see Q factor
- tidal quality factor (tidal Q): measure of orbital energy dissipated per orbit due to tidal forces
- tidal quality factor: see Q factor
- tidal radius (Hill radius): radius of gravitational influence of a body
- tidal shell: see shell galaxy
- tidal stream: see stellar stream
- tidal arm: arm of gas and potentially stars leading from a galaxy
- tidal stripping: see tidal arm
- tidal tail: string of mass ejected by a tidal forces in a neutron star merger
- tidal tail (tidal arm): arm of gas and potentially stars leading from a galaxy
- tidal theory
- tidal working (tidal heating): heating due to friction from motions caused by tidal force
- tidal-capture binary: see binary star
- tidal-capture binary: see tidal capture
- tidal-tail galaxy: see tidal arm
- tidally excited oscillation: see tidal migration
- tide: effect of Moon's gravity on Earth's seas, etc.
- TIDI: see TIMED
- TIE (Telescopes in Education): program giving grade-school students access to robotic telescopes
- TIFKAM: see Hiltner Telescope
- TIFR (Tata Institute of Fundamental Research - India): Indian math and science research institute
- TIFR GMRT Sky Survey: see Giant Metrewave Radio Telescope
- tiger stripes: see Enceladus
- Tillinghast: see Fred Lawrence Whipple Observatory
- Tillotson EoS (Tillotson equation): equation of state for high speed impacts
- Tillotson equation: equation of state for high speed impacts
- Tillotson equation of state (Tillotson equation): equation of state for high speed impacts
- tilt (obliquity): angle between an object's rotational and orbital axes
- tilt erosion: see obliquity
- TIM: planned balloon-borne 2 m telescope and spectrometer
- TIME (Tomographic Ionized-carbon Mapping Experiment): instrument in development to map the [CII] line
- time
- BJD: barycentric Julian day
- cosmic time: time since the Big Bang
- epoch: when an object was at a particular set of celestial coordinates
- epoch B1950.0: midnight 1/1/1950 GMT as used as a time reference
- epoch J2000.0: noon 1/1/2000 GMT as used as a time reference
- equinox: point-in-time when tilt of Earth is neither toward nor away from the Sun
- gigayear: a billion years
- Hubble time: approximation of the age of the universe
- Julian calendar: calendar of 365 days and a leap day once every four years
- Julian date: time in days since noon UT November 24 4714 BC Gregorian
- local noon: time at a locality when the Sun is at its highest
- local sidereal time: same as angular hours right ascension of the zenith
- sidereal: relative to the fixed position of the stars
- solar day: length of a solar system planet or Moon's day
- solar time: time based upon the position of the Sun in the Earth's sky
- Terrestrial Time: current measure of time for astronomical observations on Earth
- time standard: method of designating points in time and quantifying time periods
- timescale: general length of time something takes
- time dilation: relativity's ability to make time differ for different objects
- time domain astronomy
- Time History of Events and Macroscale Interactions during Substorms (THEMIS): set of satellites studying the Earth's magnetic field
- time scale (time standard): method of designating points in time and quantifying time periods
- time scale (timescale): general length of time something takes
- time series
- time series analysis: analysis of data points collected at uniformly-separated times
- time series data
- time standard: method of designating points in time and quantifying time periods
- time system (time standard): method of designating points in time and quantifying time periods
- time zone
- solar time: time based upon the position of the Sun in the Earth's sky
- time-delay cosmology: working out space geometry from delays due to gravitational lensing
- time-domain astronomy: observing and analyzing changes in astronomical objects
- TIME-EXT: see Tomographic Ionized-carbon Mapping Experiment
- time-like: see spacetime diagram
- geodesic: equivalent to a straight line within curved space
- TIME-NG: see Tomographic Ionized-carbon Mapping Experiment
- time-of-flight spectrometer: see particle spectrometer
- time-ordered data: observation data arranged by the time it was received
- TIME-pilot: see Tomographic Ionized-carbon Mapping Experiment
- TIMED: space probe observing Earth upper atmosphere for solar effects
- timescale: general length of time something takes
- timestream: stream of digital data representing measurements taken over time
- timing
- timing noise: see pulsar timing array
- TIMMI-2: see ESO 3.6m Telescope
- TIMMI2: see New Technology Telescope
- Tinsley-Wallerstein diagram ([α/Fe] versus [Fe/H] diagram): diagram indicating stars' degree of alpha enhancement
- TiNy Titans: study of dwarf galaxy pairs
- TiO: see titanium
- tip of the red-giant branch: standard candle consisting of the brightest RGB stars
- TIR (thermal infrared): infrared emission due to black body radiation
- TIR (total infrared): typically meaning a wide wavelength range covering NIR to FIR
- TIR: see Hayabusa2
- tired light: an alternate theory explaining the cosmological redshift
- Titan: well-known Saturn moon
- Cassini: explorer spacecraft sent to Saturn
- Dragonfly: Titan flying rover under development
- moon: a planet's natural satellite, such as Earth's
- Saturn: second largest planet in the solar system
- Titan Atmospheric Model (TAM): non-gray-RT 3D model of Titan's atmosphere
- Titania: see Uranus
- moon: a planet's natural satellite, such as Earth's
- titanium: metal, Ti, atomic number 22
- titanium monoxide: see titanium
- titanium-44: see titanium
- Titius-Bode law: relationship between the distances between solar system planets
- Titius-Bode rule (Titius-Bode law): relationship between the distances between solar system planets
- titrant: see titration
- titration: analyzing a chemical solution by color change
- titrimetry (titration): analyzing a chemical solution by color change
- TJ: see rare designator prefixes
- tKID: see KID
- TKS (TESS-Keck Survey): Keck follow-up survey to TESS discoveries
- TLE (two-line element set): data format to record the position and motion of a satellite
- TLF (tremendously low frequency): presumably electromagnetic radiation, frequency below 3 Hz
- TLM: magnitude of the dimmest astronomical object you can see
- TLP (lunar transient phenomenon): observed transient on the Moon such as a flash of light
- TMC (Taurus Molecular Cloud 1): nearby star-forming region
- TMC-1 (Taurus Molecular Cloud 1): nearby star-forming region
- TMC-2: see Taurus Molecular Cloud 1
- TMC-2: see Taurus-Auriga Complex
- TMO (Table Mountain Observatory): NASA observatory near Los Angeles
- TMSS (Two Micron Sky Survey): 1969 infrared catalog produced by Caltech
- TMT (Thirty Meter Telescope): extremely large telescope planned for Hawaii
- Tmz: see rare designator prefixes
- TN (telescope nut): avid amateur telescope maker self-description
- TN: see USS Sources
- TN: see pulsar timing array
- TNG (Telescopio Nazionale Galileo): 3.58 m telescope in Canary Islands
- TNO (trans-Neptune object): minor planet beyond Neptune
- Haumea: dwarf planet discovered in 2004
- Pluto: dwarf planet formerly listed as one of the nine planets
- Sedna: distant solar system planetoid discovered in 2003
- TNOs
- TNS (Transient Name Server): online catalog of transients
- TNT (TiNy Titans): study of dwarf galaxy pairs
- TO (telescope operator): professional technical position at a research telescope site
- TO (turn-off point): point in H-R diagram of a cluster where stars turn red
- TOA: time of arrival
- TOD (time-ordered data): observation data arranged by the time it was received
- TOE (Theory of Everything): single law explaining the four forces of nature
- symmetry breaking: loss of symmetry, such as due to loss of stability in a regime change
- TOF (theory of figures): type of model relating a planet's shape to its rotation
- TOI: see Transiting Exoplanet Survey Satellite
- ExoFOP: site to facilitate exoplanet follow-up observation
- TOI 700: see TOI 700 d
- TOI 700 d: Earth-sized exoplanet in a habitable zone
- Tokyo Atacama Observatory (University of Tokyo Atacama Observatory): observatory for a 6.5 m infrared telescope under construction
- Tokyo Photoelectric Meridian Circle: Japanese telescope to determine the position of stars and planets
- Tokyo Photoelectric Meridian Circle Catalog: see Tokyo Photoelectric Meridian Circle
- Tokyo PMC Catalog: see Tokyo Photoelectric Meridian Circle
- Tol: see Cerro Tololo Inter-American Observatory
- Tolman VII object: theoretical object adhering to exact GR solution
- Tolman VII solution: see Tolman VII object
- Tolman-Oppenheimer-Volkoff equation: see Tolman-Oppenheimer-Volkoff limit
- Tolman-Oppenheimer-Volkoff limit: maximum mass of a neutron star
- Tololo: see Cerro Tololo Inter-American Observatory
- TolTEC: sensitive infrared camera under construction for the LMT
- TolTEC: see Large Millimeter Telescope
- TolTEC C2C: see TolTEC
- TolTEC FiF: see TolTEC
- TolTEC LSS: see TolTEC
- TolTEC UD: see TolTEC
- Tombaugh: see rare designator prefixes
- Tomographic Ionized-carbon Mapping Experiment: instrument in development to map the [CII] line
- tomographic magnetic imaging (Zeeman-Doppler imaging): technique for imaging stellar magnetic fields
- tomography: observation of sections of a 3D object
- Ton (Tonantzintla Surveys): surveys providing early images of quasars and Seyfert galaxies
- Tonantzintla: see Tonantzintla Surveys
- Tonantzintla Observatory
- Tonantzintla Surveys: surveys providing early images of quasars and Seyfert galaxies
- ToO: target of opportunity
- too-big-to-fail problem: see dwarf galaxy problem
- Toomre Q parameter: stability criterion for differentially rotating disks
- Toomre sequence: model relating galaxy mergers to observation
- Toomre's stability criteria: see Toomre Q parameter
- top: see flavor
- top down model: see galaxy formation
- top hat filter: type of image processing mechanism to make small objects stand out
- top quark: see particle
- top quark: see quark
- TopHat: 2001 balloon -based CMB survey
- topological defect: defect in space that could arise in the early universe
- TOPS (Toward Other Planetary Systems): workshops on developing techniques and observing programs
- toroidal: see torus coordinates
- torr: unit of pressure approximating a millimeter of mercury on Earth
- tortuosity: describes something curved with many twists and turns
- torus
- torus coordinates: coordinates for toruses
- total derivative: see partial differential equation
- total differential equation: see partial differential equation
- total duration: see transiting planet
- total energy: see relativistic energy
- total infrared: typically meaning a wide wavelength range covering NIR to FIR
- total infrared luminosity: luminosity over a wide IR range
- total mass
- total precipitable water: see precipitable water vapor
- total relativistic energy: see relativistic energy
- total solar eclipse: see solar eclipse
- TOURNESOL: see GRANAT
- TOV (Tolman-Oppenheimer-Volkoff limit): maximum mass of a neutron star
- TOV equation: see Tolman-Oppenheimer-Volkoff limit
- Toward Other Planetary Systems: workshops on developing techniques and observing programs
- tower: see solar telescope
- TP (thermal pulse): pulse in an AGB star due to helium fusion in a shell
- TP-AGB: see asymptotic giant branch
- thermal pulse: pulse in an AGB star due to helium fusion in a shell
- TPC: see thermal pulse
- TPCI: see Cloudy
- TPF (Terrestrial Planet Finder): plan for space telescopes to find smaller exoplanets
- TPW: see precipitable water vapor
- TR: see OGLE
- TRACE: former solar observing satellite
- Trace Gas Orbiter: ESA and Russian Mars orbiter-probe launched in 2016
- tracer: chemical whose detection indicates the presence of something else
- Tracking and Data Relay Satellite System: NASA satellites used for communication and tracking of space probes
- Tracklet-less Heliocentric Orbit Recovery: see ADAM::THOR
- trade winds
- traditional approximation of rotation: approximation of waves on a rotating body
- training
- Trans-Atlantic Exoplanet Survey: 2000s exoplanet-search survey using three telescopes
- trans-iron element: elements with atomic number greater than that of iron
- trans-Neptune binary: see binary minor planet
- trans-Neptune object: minor planet beyond Neptune
- trans-Neptune objects
- trans-Neptunian object (trans-Neptune object): minor planet beyond Neptune
- transfer equation (equation of radiative transfer): equation describing energy transfer by EMR
- transformation group
- transient: observed change in the sky
- AT2018cow: unusual 2018 optical transient
- AT2019dsg: 2019 TDE undergoing study
- FRB121102: first repeating FRB discovered
- GW170817: 2017 gravitational wave detection from a neutron star merger
- Kepler's Supernova: Type Ia supernova observed in 1604 by Johannes Kepler
- lunar transient phenomenon: observed transient on the Moon such as a flash of light
- Oh-My-God Particle: extremely energetic particle from space detected in 1991
- SN 1572: Type Ia supernova noted in 1572 by Tycho Brahe
- SN 185: supernova recorded in China in AD 185
- SN 1987A: supernova in February 1987 rare for being visible by the naked eye
- SN 2014J: Type Ia supernova in Messier 82, the Cigar Galaxy
- stellar merger: two stars combining into one
- transient astronomical event (transient): observed change in the sky
- transient astronomical event: see transient astronomy
- transient astronomy: study of short-term astronomical phenomena
- Transient High Energy Sky and Early Universe Surveyor (THESEUS): plan for X-ray/Gamma-ray transient space mission
- transient lunar phenomenon (lunar transient phenomenon): observed transient on the Moon such as a flash of light
- Transient Name Server: online catalog of transients
- transient type
- transients
- transit: a celestial body passing between another and an observer
- transit: see meridian circle
- transit: see transit telescope
- occultation: one celestial body hiding another from an observer
- transit circle (meridian circle): instrument for timing the passage of stars over a meridian
- transit depth: see transiting planet
- transit duration: see transiting planet
- transit duration variations: see transit timing variations
- transit mapping: see eclipse mapping
- transit method: method of detecting exoplanets and binary companions
- transit method: see extra-solar planet
- transit method: see transit
- EXOFAST: code to match model parameters with exoplanet observation data
- GJ 1132 b: Earth-like extrasolar planet discovered in 2015
- GJ 1214 b: super-Earth extrasolar planet discovered in 2009
- HAT-P-7b: hot Jupiter discovered in 2008
- HD 189733 b: hot Jupiter orbiting an orange dwarf
- K2-18b: super-Earth in a habitable zone
- Kepler-1625b: giant exoplanet in a star's habitable zone
- Kepler-16b: exoplanet orbiting a binary star
- Kepler-186f: Earth-like exoplanet in a star's habitable zone
- Kepler-452b: Earth-like exoplanet discovered in 2015
- LHS 3844 b: rocky planet in habitable zone of a red dwarf
- TOI 700 d: Earth-sized exoplanet in a habitable zone
- transiting planet: planet crossing between another body and the observer
- WASP-12b: retrograde hot Jupiter discovered in 2008
- WASP-33b: hot Jupiter discovered in 2010
- WASP-43b: hot Jupiter with especially small orbit
- WASP-67b: hot Jupiter discovered in 2011
- XO-3b: unusual hot Jupiter
- transit radio telescope
- transit spectrography (transit spectroscopy): spectroscopy through an exoplanet's transit
- transit spectrometer: see transit spectroscopy
- transit spectroscopy: spectroscopy through an exoplanet's transit
- transit telescope: telescope able to shift aim up/down but not horizontally
- meridian circle: instrument for timing the passage of stars over a meridian
- transit timing variations: variations in the timing of the transits of exoplanets and binaries
- transiting exoplanet: see transiting planet
- Transiting Exoplanet Survey Satellite: observatory-satellite searching for transiting exoplanets
- transiting planet: planet crossing between another body and the observer
- transit: a celestial body passing between another and an observer
- Transiting Planets and Planetesimals Small Telescope (TRAPPIST): a ground-based automated transiting-planet finding telescope
- transition disk (transitional disk): disk with inner part cleared
- transition edge sensor: sensor using superconductivity's strong temperature sensitivity
- transition edge sensor bolometer: see transition edge sensor
- transition region: middle layer of the Sun's atmosphere
- Transition Region and Coronal Explorer (TRACE): former solar observing satellite
- transitional disk: disk with inner part cleared
- transitional planet (mini-Neptune): planet with characteristics a bit like Earth but more like Neptune
- transitional planet: see super-Earth
- transits
- Transits of Extrasolar Planets: late 1990s search for transiting planets
- transmission spectrography (transmission spectroscopy): spectrum of radiation passing through a substance
- transmission spectroscopy: spectrum of radiation passing through a substance
- transmissive grating: see grating
- transonic: see Mach number
- transport-limited: see weathering
- transverse velocity: see radial velocity
- Trapezium Cluster: open cluster of stars in Orion Nebula
- TRAPPIST: a ground-based automated transiting-planet finding telescope
- TRAPPIST telescope
- TRAPPIST-1: red dwarf with exoplanets within the habitable zone
- TRAPPIST-1b: see TRAPPIST-1
- TRAPPIST-1c: see TRAPPIST-1
- TRAPPIST-1d: see TRAPPIST-1
- TRAPPIST-1e: see TRAPPIST-1
- TRAPPIST-1f: see TRAPPIST-1
- TRAPPIST-1g: see TRAPPIST-1
- TRAPPIST-1h: see TRAPPIST-1
- TRAPPIST-North: see TRAPPIST
- TRAPPIST-South: see TRAPPIST
- Traverse Gravimeter Experiment
- TRC: see Hipparcos
- treasury: see legacy survey
- Treasury Program: see legacy survey
- treasury survey: see legacy survey
- tree
- dendrogram: diagram of a "tree", i.e., of a graph without cycles
- tremendously low frequency: presumably electromagnetic radiation, frequency below 3 Hz
- TrES (Trans-Atlantic Exoplanet Survey): 2000s exoplanet-search survey using three telescopes
- TRGB (tip of the red-giant branch): standard candle consisting of the brightest RGB stars
- Tri II (Triangulum II): dwarf galaxy in the Local Group
- Triana (DISCOVR): space weather satellite
- Triangulum (Triangulum Galaxy): small spiral galaxy in the Local Group
- Triangulum Galaxy: small spiral galaxy in the Local Group
- Triangulum II: dwarf galaxy in the Local Group
- Triangulum subgroup
- triaxial
- spheroid: sphere-like shape that is flattened or elongated
- triaxial galaxy
- trigonometric parallax (parallax): angle due to different lines of sight
- triple alpha process: fusion reaction chain turning helium-4 into carbon
- triple bond: see hydrocarbon
- triple point
- Mars: well-explored planet in the solar system
- supercritical fluid: state of matter at sufficient pressure and temperature
- triple prism spectrograph: see spectroscopy
- triple star: see star system
- triple system
- TripleSpec: near-infrared spectrograph on the Hale Telescope
- TripleSpec: see Hale Telescope
- TripleSpec 4.1: see SOAR Telescope
- TripleSpec 4.1: see TripleSpec
- Triplespec 4.1: see Víctor M. Blanco Telescope
- TripleSpec Exoplanet Discovery Instrument: see TripleSpec
- TripleSpec Externally Dispersed Interferometry: see TripleSpec
- tritium: see deuterium
- tritium: see hydrogen
- KATRIN: experiment to measure neutrino mass
- Project 8: experiment in development to measure neutrino mass
- Triton: Neptune's one significant moon
- Triton: see Neptune
- irregular moon: moon with an atypical orbit, such as retrograde
- moon: a planet's natural satellite, such as Earth's
- Moon formation: process by which the Moon and other moons formed
- Trojan: see asteroid belt
- Trojan asteroid: see asteroid belt
- Lagrangian point: points around two orbiting bodies where small objects can sit
- Lucy: space probe to observe Jupiter Trojan asteroids
- Trojan planet: see Lagrangian point
- Trojan point: see Lagrangian point
- Lucy: space probe to observe Jupiter Trojan asteroids
- Trojans' Odyssey (Lucy): space probe to observe Jupiter Trojan asteroids
- Tropic of Cancer: see circle of latitude
- Tropic of Capricorn: see circle of latitude
- tropical year: see Julian calendar
- tropical year: see sidereal
- tropopause: see atmospheric temperature profile
- troposphere: see atmospheric temperature profile
- true anomaly: see mean anomaly
- true vacuum: see false vacuum
- Big Crunch: theoretical end of universe drawn together by gravity
- Trumpler: see rare designator prefixes
- TS: see rare designator prefixes
- Tsol: see Titan
- TSpec (TripleSpec): near-infrared spectrograph on the Hale Telescope
- tsunami
- TSUNAMI: few-body code
- tSZ: see Sunyaev-Zel'dovich effect
- tSZE: see Sunyaev-Zel'dovich effect
- TT (Terrestrial Time): current measure of time for astronomical observations on Earth
- TT: see CMB polarization
- TT: see time standard
- TTCam: see Lucy
- TTCam-1: see Lucy
- TTCam-2: see Lucy
- TTM: see Kvant 1
- TTS (T-Tauri star): type of variable pre-main-sequence star
- TTV (transit timing variations): variations in the timing of the transits of exoplanets and binaries
- TTV method: see transit timing variations
- Tubingen Ultraviolet Echelle Spectrometer: 1990s UV spectrometer used on two Space Shuttle missions
- Tuc-Hor (Tucana Horologium association): nearby stellar association
- Tucana Horologium association: nearby stellar association
- TUES (Tubingen Ultraviolet Echelle Spectrometer): 1990s UV spectrometer used on two Space Shuttle missions
- Tully-Fisher relation: relation between spiral galaxy luminosity and line width
- TuMAG: see SUNRISE
- tuning fork: see galaxy classification
- Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy (Tunka experiment): Russian Cherenkov detector aimed at cosmic rays and gamma rays
- Tunka experiment: Russian Cherenkov detector aimed at cosmic rays and gamma rays
- tunnel diode
- tunneling (quantum tunneling): quantum mechanical effect of particles passing through a barrier
- turbopause (homopause): level of atmosphere up to which components are mixed
- turbulence: irregular flow of a fluid
- turbulence pressure (turbulent pressure): pressure component due to the presence of turbulence
- turbulent flow (turbulence): irregular flow of a fluid
- turbulent pressure: pressure component due to the presence of turbulence
- turn-off (turn-off point): point in H-R diagram of a cluster where stars turn red
- turn-off point: point in H-R diagram of a cluster where stars turn red
- Turner: see rare designator prefixes
- Turtlebeach: radiative transfer code
- TVLM: see rare designator prefixes
- TW Hya (TW Hydrae): nearest T-Tauri star
- TW Hydrae: nearest T-Tauri star
- TW Hydrae association: nearby stellar association
- TW-1 (Tianwen-1): active Chinese Mars rover/orbiter mission
- TWA (TW Hydrae association): nearby stellar association
- TWA star: see TW Hydrae association
- Twin Astrograph Catalog: see USNO Twin Astrograph
- twinkle
- point source: celestial object that focuses to a point or single Airy disk
- twinkling: blinking, apparent movement and color changes of observed stars
- two dimensional model: see three dimensional model
- Two Micron All-sky Survey: near-infrared survey of both hemispheres
- Two Micron Sky Survey: 1969 infrared catalog produced by Caltech
- two-body problem: see N-body problem
- two-line element set: data format to record the position and motion of a satellite
- two-photon emission: see continuum emission
- two-stream approximation: approximation of a star's internal EMR's divergence from isotropic
- twotino: see plutoid
- TXFS: see rare designator prefixes
- TXS (Texas Survey of Radio Sources at 365 MHz): 1970s/1980s radio survey made with the Texas Interferometer
- TXS 0506+056: blazar that is a neutrino source
- neutrino hotspot: region of sky from which significant neutrinos have been detected
- TYC: see Hipparcos
- TYCHO: stellar evolution code
- Tycho Catalog: see Hipparcos
- Tycho Input Catalog: see Hipparcos
- Tycho Reference Catalog: see Hipparcos
- Tycho SNR: see SN 1572
- Tycho's Supernova (SN 1572): Type Ia supernova noted in 1572 by Tycho Brahe
- Tycho's supernova
- Tycho-1 Catalog: see Hipparcos
- Tycho-2 Catalog: see Hipparcos
- Type 1 AGN: see active galactic nucleus
- Type 1 Seyfert galaxy: see Seyfert galaxy
- Type 2 AGN: see active galactic nucleus
- Type 2 Seyfert galaxy: see Seyfert galaxy
- Type 3 Seyfert galaxy: see Seyfert galaxy
- LINER: galaxy nucleus emitting spectral lines for ionized and neutral atoms
- Type A CAI: see CAI
- Type B CAI: see CAI
- Type C CAI: see CAI
- Type I Cepheid: see Cepheid variable
- Type I galaxy cluster: see Bautz-Morgan classification
- Type I migration: see planetary migration
- Type I SLSN: see superluminous supernova
- Type I supernova
- Type I-II galaxy cluster: see Bautz-Morgan classification
- Type Ia supernova: type of supernova for which distance can be determined
- Type Ia supernova problem: lack of fully-convincing Type Ia supernovae triggering model
- Type Ia supernova progenitor: see supernova progenitor
- Type Ia supernova survey: see supernova survey
- Type Ib supernova: see core collapse supernova
- Type Ib supernova: see supernova
- Type Ic BL supernova
- Type Ic supernova: see core collapse supernova
- Type Ic supernova: see supernova
- Type II Cepheid: see Cepheid variable
- Type II galaxy cluster: see Bautz-Morgan classification
- Type II migration: see planetary migration
- Type II SLSN: see superluminous supernova
- Type II supernova (core collapse supernova): supernova resulting from the collapse of the core of a star
- supernova: stellar explosion larger than a nova
- Type II-III galaxy cluster: see Bautz-Morgan classification
- Type II-L supernova: see supernova
- Type II-P supernova: see supernova
- Type IIb: see supernova
- Type III galaxy cluster: see Bautz-Morgan classification
- Type III migration: see planetary migration
- Type IIIE galaxy cluster: see Bautz-Morgan classification
- Type IIIS galaxy cluster: see Bautz-Morgan classification
- Type IIn supernova: see supernova
- TZO (Thorne-Żytkow object): giant star with a neutron star at its center
Index