This is a list of exoplanet discoveries that were the first by several criteria, including:
the detection method used, the planet type, the planetary system type, the star type, and others.
The first The choice of "first" depends on definition and confirmation, as below. The three systems detected prior to 1994 each have a drawback, with Gamma Cephei Ab being unconfirmed until 2002; while the PSR B1257+12 planets orbit a pulsar. This leaves 51 Pegasi b (discovered and confirmed 1995) as the first confirmed exoplanet around a non-compact star. First Planet Star Year Notes First detected exoplanet later confirmed Gamma Cephei Ab Gamma Cephei 1988 (suspected), 2002 (confirmed) First evidence for exoplanet to receive later confirmation. First exoplanets to be confirmed PSR B1257+12 BPSR B1257+12 C PSR B1257+12 1992 First super-Earths.Space.com, "Earth-Sized Planets Confirmed, But They're Dead Worlds", Robert Roy Britt, 29 May 2003 (accessed 20-10-2010) These exoplanets orbit a pulsar. First confirmed exoplanet around non-compact star 51 Pegasi b 51 Pegasi 1995 First convincing exoplanet discovered around a Sun-like star. While the minimum mass of HD 114762 b was high enough (11 Jupiter-masses) that it could be a brown dwarf, 51 Peg b's minimum mass meant that it almost certainly was near the mass of Jupiter.
By discovery method + First discovery by a method Discovery method Planet Star Year Notes First planet discovered via pulsar timing PSR B1257+12 BPSR B1257+12 C PSR B1257+12 1992 First super-earths. First planet discovered via radial velocity 51 Pegasi b 51 Pegasi 1995 First convincing exoplanet discovered around a Sun-like star. While the minimum mass of HD 114762 b was high enough (11 Jupiter-masses) that it could be a brown dwarf, 51 Peg b's minimum mass meant that it almost certainly was near the mass of Jupiter. First planet discovered via transit OGLE-TR-56 b OGLE-TR-56 2002SpaceDaily.com, "Farthest Known Planet Opens the Door For Finding New Earths", 10 January 2003 (accessed 2010-10-24) This was also the second planet detected through transiting, and the then farthest planet known at time of discovery. The first extrasolar planet detected to be transiting was HD 209458 b, which had already been discovered by the radial velocity method.PhysOrg.com, "New Era in Planetary Science", 23 March 2005 (accessed 2010-10-24) First planet discovered via gravitational lensing / 2004 This was discovered independently by the OGLE and MOA teams.Sky and Telescope, "First Planet Found by Microlensing", Alan M. MacRobert, 16 April 2004 (accessed 2010-10-24)First planetary-mass companion discovered by direct imaging2M1207 b2M12072004/ 2005May be a sub-brown dwarf instead of a planet, depending on formation mechanism and definitions chosen.ESO press releases First directly imaged extrasolar planet discovered orbiting a star DH Tauri b DH Tauri 2005 Revised masses place it below the deuterium-burning limit.Mass was revised to about 11.5 Jupiter masses in 2006. May be a brown dwarf companion. DH Tauri b and GQ Lupi b were confirmed as companions within about three month in 2005. Both could be brown dwarfs. If one is a planet, it is the first planet orbiting a 'normal' star, possibly the first exoplanet directly imaged. First planet discovered through variable star timing V391 Pegasi b V391 Pegasi 2007 The planet was discovered by examining deviations from pulsation frequency from a subdwarf star. First extrasolar planet discovered by indirect imaging (visible light) Fomalhaut b Fomalhaut 2008 Discovered by a light reflecting off of a dust cloud surrounding the planet. First planet orbiting an ABO star. In 2020 this object was determined to be an expanding debris cloud from a collision of asteroids rather than a planet. First extrasolar planet discovered by astrometric observations HD 176051 b HD 176051 A or HD 176051 B 2010 Orbits around one of the stars in a binary star system although it is not known which component it is orbiting around. First exoplanet discovered by orbital perturbations of another planet Kepler-19c Kepler-19 (KOI-84, TYC 3134-1549-1) 2011 Detected through transit-timing variation method. Its existence was inferred by the gravitational influence it had on the orbital periodicity of Kepler-19b.TG Daily, "'Invisible' planet detected", Kate Taylor, 9 September 2011Time, "Found: A (So Far) Invisible World", Michael D. Lemonick, 9 September 2011 First exoplanets discovered by orbital phase reflected light variations Kepler-70b, Kepler-70c Kepler-70 2011 Now dubious. First exoplanet discovered by transit-duration variation method Kepler-88c Kepler-88 (KOI-142) 2013 Both transit timing variation and transit-duration variation was measured to measure deviations from the regular orbit of Kepler-88b. Deviations of the planet's transit duration and timing helped to discover Kepler-88c.First exoplanet discovered by spectral template matching with moderate-resolution spectroscopyBeta Pictoris dBeta Pictoris2026This was simultaneously discovered by two independent teams, using spectral template matching and direct imaging.
By detection method Some of these planets had already been discovered by another method but were the first to be detected by the listed method.
+ First detection by a method Detection method Planet Star Year Notes First planet detected via radial velocity Gamma Cephei Ab Gamma Cephei 1988 First evidence for exoplanet to receive later confirmation. First planet detected via pulsar timing PSR B1257+12 BPSRB1257+12 C PSR B1257+12 1992 First planet detected by transit method HD 209458 b HD 209458 1999 This first exoplanet found to be transiting had already been discovered by the radial velocity method. This is also the first planet that has been detected through more than one method. First planetary-mass companion directly imaged (infrared) 2M1207 b 2M1207 2004/ 2005 May be a sub-brown dwarf instead of a planet, depending on formation mechanism and definitions chosen. If it is a planet, it is the first known planet around a brown dwarf. First directly imaged extrasolar planet orbiting a star (infrared) DH Tauri b DH Tauri 2005 Revised masses place it below the deuterium-burning limit. May be a brown dwarf companion. DH Tauri b and GQ Lupi b were confirmed as companions within about three month in 2005. Both could be brown dwarfs. If one is a planet, it is the first planet orbiting a 'normal' star, possibly the first exoplanet directly imaged. First planet with observed secondary eclipse (infrared) HD 209458 b HD 209458 2005 Planet was discovered in 1999. This is the first detection of light from an object with a clear planetary origin. First directly imaged extrasolar planet orbiting a sun-like star (infrared) AB Pictoris b AB Pictoris 2005 It has MJ. GQ Lupi b was found earlier. May, however, be a brown dwarf companion.
1RXS J160929.1−210524 b was found later.Exoplanet 'circles normal star', BBC News Online, September 15, 2008 Revised mass places it at or above the deuterium-burning limit. May be a sub-brown dwarf instead of a planet, depending on formation mechanism and definitions chosen. The orbital status of the companion was confirmed in 2010.First planet characterized by atmospheric spectroscopyHD 209458 bHD 2094582007 also by HD 189733 b was characterized spectroscopically only few month later. Any of the earlier Direct imaging exoplanets, e.g. 2M1207 b, DH Tauri b or GQ Lupi b have spatially resolved spectroscopic observations, but the objects need confirmation to be of planetary origin. First extrasolar planet detected by indirect imaging (visible light) Fomalhaut b Fomalhaut 2008 Discovered by a light reflecting off of a dust cloud surrounding the planet. First planet orbiting an ABO star. In 2020 this object was determined to be an expanding debris cloud from a collision of asteroids rather than a planet. First planets directly characterized through astrometric observations Gliese 876 b and Gliese 876 c Gliese 876 2009 First planet detected by orbital phase reflected light variations in visible light CoRoT-1b CoRoT-1 2009 The planet in question had already been discovered with transit method.First planet characterized by spatially resolved atmospheric spectroscopyHR 8799 cHR 87992010 Several spectra of Direct imaging exoplanets might be earlier, but the objects need confirmation to be of planetary origin. Especially AB Pictoris b is a candidate, if its mass is confirmed to be MJ. First planets detected through ellipsoidal light variations of the host star HAT-P-7b HAT-P-7 2010 First planets detected through transit timing variation method Kepler-9b, Kepler-9c Kepler-9 2010 Transit-timing variation was used to confirm both planets detected through transit method. First planet detected through transit duration variation method Kepler-16b Kepler-16 2011 Orbital motion of the three-body system Kepler-16 causes variations of the duration of stellar eclipses and planetary transits. First planet detected with eclipsing binary timing with well-characterized orbit Kepler-16b Kepler-16 2011 Kepler-16b itself was detected through transit method. There are stars with earlier detections through eclipsing binary timing. However, either those signals have matched with unstable orbits or the exact orbits are not known. First planet detected by light variations due to relativistic beaming TrES-2b TrES-2A 2012First tilted multi-planetary system discoveredKepler-56b, c and dKepler-562013 First extrasolar planet detected through polarimetry DH Tauri b / GSC 6214-210 b DH Tauri / GSC 6214–210 2021 "polarization of several tenths of a percent for DH Tau B and GSC 6214-210 B in H-band" ... "unlikely to be caused by interstellar dust." ... "the polarization most likely originates from circumsubstellar disks." Both companions may be brown dwarfs or exoplanets. Polarized scattered light was found for HD 189733 b in 2008. It could not be confirmed and was disputed by two separate teams. Possibly a "Saharan dust event over the La Palma observatory in 2008 August". HD 189733 b was discovered in 2005.
By system type + First discovery by system type System type Planet Star Year Notes First extrasolar planet discovered in a solitary star system PSR B1257+12 BPSR B1257+12 C PSR B1257+12 1992 First extrasolar planets discovered.Space.com, "Out There: A Strange Zoo of Other Worlds", Charles Q. Choi, 14 February 2010 (accessed 2010-10-20) First multiple planet extrasolar system discovered PSR B1257+12 APSR B1257+12 BPSR B1257+12 C PSR B1257+12 1992 First pulsar planetary system. First planet discovered in a circumbinary orbit PSR B1620-26 b PSR B1620-26 1993 Orbits a pulsar and a white dwarf. Discovery confirmed in 2003. First planet discovered in globular cluster PSR B1620-26 b PSR B1620-26 1993 Located in Messier 4. First planet discovered in a multiple main-sequence star system 55 Cancri Ab 55 Cancri A 1996 55 Cnc has a distant red dwarf companion. The planet around Gamma Cephei was already suspected in 1988, although its existence was not confirmed until 2002 Gamma Cephei Ab is the first relatively close binary with a planet. First "free-floating" planet discoveredSuperjovian free-floating objects are not always considered planets due to the gray area between planets and brown dwarfs S Ori 68 2000 ~5 MJupiter Isolated status needs confirmation. Could be a companion of SE 70; needs confirmation.