Term Index (J)

Astrophysics (Index)

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Term Index (J)

J:
- emission coefficient (j): measure of how much light a substance emits
- joule (J): SI unit of energy
- specific angular momentum (J): absolute angular momentum divided by mass
J band:
- infrared (IR): electromagnetic radiation, wavelength 0.74-300 micrometers
J coefficients:
- J₂: geopotential coefficient regarding a planet's oblateness
J designator: designator using equatorial coordinates at year 2000
J-MAG:
- JUICE: mission to Jupiter in development
J-type shock:
- shock wave: abrupt propagating disturbance in a fluid
J1407: star orbited by a companion with a ring system
J1713-0747: binary system with millisecond pulsar and white dwarf
J2000:
- epoch J2000.0: noon 1/1/2000 GMT as used as a time reference
J2000 epoch:
- epoch: when an object was at a particular set of celestial coordinates
J2000 equinox:
- equinox: times when tilt of Earth is neither toward or away from the Sun
J2000.0:
- epoch J2000.0: noon 1/1/2000 GMT as used as a time reference
- terrestrial time (TT): current measure of time for astronomical observations on Earth
J2000.0 epoch:
- epoch: when an object was at a particular set of celestial coordinates
J2000.0 equinox: equinox as of the J2000.0 epoch used as a positional reference
- equinox: times when tilt of Earth is neither toward or away from the Sun
J20000 epoch:
- epoch: when an object was at a particular set of celestial coordinates
J₂: geopotential coefficient regarding a planet's oblateness
J₃:
- J₂: geopotential coefficient regarding a planet's oblateness
Jacobi constant:
- Jacobi integral: method of solving some three-body problems
Jacobi integral: method of solving some three-body problems
Jacobus Kapteyn Telescope:
- Isaac Newton Group of Telescopes (ING): three telescopes in Canary Islands
- Roque de los Muchachos Observatory (ORM,LPO,NHO): observatory at La Palma in the Canary Islands
JADE:
- Juno: mission to Jupiter
James Clerk Maxwell Telescope (JCMT): far-infrared telescope in Hawaii
- East Asian Observatory (EAO): operator of JCMT
James Webb Space Telescope (JWST): future space-based 6.5 meter infrared telescope
- CSA: includes astronomical research
Jansky:
- jansky (Jy): unit of measurement of spectral flux density
- Very Large Array (VLA): radio telescope in New Mexico
JANUS:
- JUICE: mission to Jupiter in development
Japan:
- Japan Aerospace Exploration Agency (JAXA): Japan agency includes astronomical research
- KAGRA: gravitational wave detector in Japan preparing for operation
- National Astronomical Observatory of Japan (NAOJ): Japanese astronomy organization
- Publications of the Astronomical Society of Japan (PASJ): bimonthly journal
- TAMA 300: small prototype gravitational wave detector in Japan
- VERA: VLBI project to map the Milky Way
Japan Aerospace Exploration Agency (JAXA): Japan agency includes astronomical research
Japanese:
- AKARI: Japanese space infrared telescope
- ASTRO-H: Japanese space X-ray telescope
- MAXI: Japanese X-ray camera on the International Space Station
- SELENE: 2007-2008 Japanese lunar probe
- Yohkoh: 1990s Japanese solar observatory spacecraft
JAXA:
- AKARI: Japanese space infrared telescope
- ASCA: 1990s Japanese space X-ray telescope
- ASTRO-H: Japanese space X-ray telescope
- BepiColombo: mission to Mercury
- Ginga: 1980s Japanese space X-ray telescope
- Japan Aerospace Exploration Agency (JAXA): Japan agency includes astronomical research
- LiteBIRD: planned spacecraft to map CMB polarization
- MMX: Japanese probe to bring back a sample of a Martian moon
- SELENE: 2007-2008 Japanese lunar probe
- SPICA: plan for a future space IR telescope
- Suzaku: space X-ray telescope
- Yohkoh: 1990s Japanese solar observatory spacecraft
JBO:
- Jodrell Bank Observatory (JBO): radio observatory in England
- Mark II (MKII): 38 m radio telescope in England
- MERLIN: VLBI array spread across England
JCM:
- Juno: mission to Jupiter
JCMT:
- East Asian Observatory (EAO): operator of JCMT
- James Clerk Maxwell Telescope (JCMT): far-infrared telescope in Hawaii
- Mauna Kea: Hawaiian mountain, the site of observatories
- Mauna Kea Observatories (MKO): observatories on Mauna Kea in Hawaii
JD:
- Julian date (JD): time in days since noon UT November 24 4714 BC Gregorian
JDEM:
- Roman Space Telescope (RST,WFIRST): proposed near-infrared space observatory
JDN:
- Julian date (JD): time in days since noon UT November 24 4714 BC Gregorian
Jeans criterion:
- Jeans length: critical radius below which gravity will collapse a cloud
Jeans density:
- Jeans length: critical radius below which gravity will collapse a cloud
Jeans escape: type of ongoing escape of gas particles from atmosphere
- atmospheric escape: escape of gas particles from a planet's atmosphere
- hydrodynamic escape: ongoing escape of gas particles from atmosphere
- Jeans parameter (λ): ratio measuring a tendency of an atmosphere to escape
Jeans instability:
- Jeans length: critical radius below which gravity will collapse a cloud
Jeans length: critical radius below which gravity will collapse a cloud
Jeans mass:
- Jeans length: critical radius below which gravity will collapse a cloud
Jeans parameter (λ): ratio measuring a tendency of an atmosphere to escape
Jeans swindle:
- Jeans length: critical radius below which gravity will collapse a cloud
JEDI:
- Juno: mission to Jupiter
jellyfish galaxy: galaxy with a gas tail including star formation
JEM-X:
- INTEGRAL: European gamma ray observatory-satellite
jet: stream of matter from an astronomical body
- 3C 273: first quasar discovered
- 3C 303: Seyfert galaxy
- 3C 9: first quasar discovered
- Cygnus A (3C 405,QSO B1957+405): early-discovered radio galaxy and quasar
- M87: supergiant elliptical galaxy in local universe
- superrotating wind: wind traveling in the same direction as the planet is rotating
- zonal flow: east-west air circulation
- zone: apparent "horizontal" band in an atmosphere
jet current: electric current within a plasma jet
jet stream:
- jet: stream of matter from an astronomical body
- superrotating wind: wind traveling in the same direction as the planet is rotating
- thermal wind: wind from pressure and the Coriolis force varying with altitude
- zonal flow: east-west air circulation
JET-X:
- Spektr-RG (SRG, SXG): Russian-German X-ray observatory launched in 2019
jets:
- bipolar outflow: streams of matter from the poles of a protostar
- Herbig-Haro object (HH,HHO): illuminated nebula from colliding jets
- jet current: electric current within a plasma jet
- mass loading: moving gas gaining mass from clouds or stars
- microquasar: stellar-sized black hole with quasar-like activity
- quasar (QSO): distant, bright object that appears something like a star
- relativistic beaming: directional relativistic effect on light from relativistic speeds
JHK:
- JHK photometric system (JHK): system to classify stars according to near-infrared colors
JHK photometric system (JHK): system to classify stars according to near-infrared colors
JIRAM:
- Juno: mission to Jupiter
JKT:
- Isaac Newton Group of Telescopes (ING): three telescopes in Canary Islands
- Roque de los Muchachos Observatory (ORM,LPO,NHO): observatory at La Palma in the Canary Islands
Jodrell Bank Experimental Station:
- Jodrell Bank Observatory (JBO): radio observatory in England
Jodrell Bank Mark II:
- Mark II (MKII): 38 m radio telescope in England
Jodrell Bank Observatory (JBO): radio observatory in England
- Mark II (MKII): 38 m radio telescope in England
- MERLIN: VLBI array spread across England
John A. Galt Telescope:
- Dominion Radio Astrophysical Observatory (DRAO): radio observatory in British Columbia, Canada
Johns Hopkins University:
- Space Telescope Science Institute (STScI): science operator of space telescopes
Johnson system:
- UBV photometric system: commonly-cited photometric system for describing stars' colors
- Vega system: magnitude calibration such that Vega has zero magnitude
Johnson-Cousins system:
- I band: photometric filter for near infrared light
- UBV photometric system: commonly-cited photometric system for describing stars' colors
Johnson-Morgan System:
- UBV photometric system: commonly-cited photometric system for describing stars' colors
Johnson-Nyquist noise:
- thermal noise: noise inherent in electronic component warmer than absolute zero
JOI:
- Juno: mission to Jupiter
Joint Dark Energy Mission:
- Roman Space Telescope (RST,WFIRST): proposed near-infrared space observatory
joule (J): SI unit of energy
Joule heating:
- Ohmic heating: heating resulting from an electric current through a material
journal:
- Publications of the Astronomical Society of Japan (PASJ): bimonthly journal
- Publications of the Astronomical Society of the Pacific (PASP): monthly journal
Jovian planet:
- giant planet: planet of more than 10 Earth masses
JPA:
- Giotto: 1980s space mission carrying out a Comet Halley flyby
JPL:
- Galaxy Evolution Explorer (GALEX): observatory-satellite with 50-cm ultraviolet telescope
JUICE: mission to Jupiter in development
Julian date (JD): time in days since noon UT November 24 4714 BC Gregorian
Julian day:
- Julian date (JD): time in days since noon UT November 24 4714 BC Gregorian
Julian day number:
- Julian date (JD): time in days since noon UT November 24 4714 BC Gregorian
Julian year:
- Julian date (JD): time in days since noon UT November 24 4714 BC Gregorian
Juno: mission to Jupiter
Juno Orbit Insertion:
- Juno: mission to Jupiter
Juno Vesta:
- asteroid: minor planet without comet characteristics
JunoCam:
- Juno: mission to Jupiter
Jupiter: largest planet in the solar system
- Callisto: well-known Jupiter moon
- Europa: well-known Jupiter moon
- Europa Clipper: planned Europa space probe
- Europa Lander: plan for a mid 2020s Europa probe landing on the surface
- Galileo: circa 1990s space mission to Jupiter
- Ganymede: well-known Jupiter moon
- helium rain: possible source of heat in giant planet atmospheres
- Io: well-known Jupiter moon
- JUICE: mission to Jupiter in development
- Juno: mission to Jupiter
- liquid planet: planet consisting of liquid
- ring system: disk or set of rings orbiting a planet
- shepherd moon: small moon at outer edge of a ring
- Voyager: space probes to observe planets and the edge of the solar system
Jupiter I:
- Io: well-known Jupiter moon
Jupiter Icy Moons Explorer:
- JUICE: mission to Jupiter in development
Jupiter II:
- Europa: well-known Jupiter moon
Jupiter III:
- Ganymede: well-known Jupiter moon
Jupiter IV:
- Callisto: well-known Jupiter moon
Jupiter mass:
- mass: object's quality that determines the effects of forces and gravity
Jupiter Orbiter Probe:
- Galileo: circa 1990s space mission to Jupiter
Jupiter Trojan:
- asteroid belt: ring of orbiting planetoids/asteroids
Jupiters:
- extra-solar planet: planet not in the solar system
JVLA:
- Very Large Array (VLA): radio telescope in New Mexico
JWST:
- CSA: includes astronomical research
- grism: combination of a grating and a prism
- James Webb Space Telescope (JWST): future space-based 6.5 meter infrared telescope
- Ultimate Spitzer Phase Curve Survey (USPCS): investigation of exoplanet atmospheres
Jy:
- jansky (Jy): unit of measurement of spectral flux density

Index