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Exoplanet List of exoplanets
WASP-121b 01.jpg
Artist's impression of WASP-121b and its host star
Parent star
Star WASP-121
Constellation Puppis[1]
Right ascension (α) 07h 10m 24.0595s[2]
Declination (δ) −39° 05′ 50.562″[2]
Apparent magnitude (mV) 10.4[3][4]
Distance850±60[2] ly
(260±20[2] pc)
Spectral type F6V[3][4]
Mass (m) 1.353[3] M
Radius (r) 1.458[3] R
Temperature (T) 6460.0[3] K
Metallicity [Fe/H] 0.13[3]
Orbital elements
Semi-major axis(a) 0.02544[3] AU
Eccentricity (e) 0.0[3]
Orbital period(P) 1.275[3] d
Inclination (i) 87.6[3]°
Physical characteristics
Mass(m)1.184[3][4] MJ
Radius(r)1.81[4] RJ
Discovery information
Discovery date 2015[3]
Discovery method Primary Transit[3]
Other detection methods Radial Velocity[3]
Discovery status Published
Database references
Extrasolar Planets
Exoplanet Archivedata
Open Exoplanet Cataloguedata

WASP-121b is an extrasolar planet orbiting the star WASP-121.[5][6] WASP-121b is the first exoplanet found to contain water in an extrasolar planetary stratosphere (i.e., an atmospheric layer in which temperatures increase as the altitude increases).[5][6] WASP-121b is in the constellation Puppis,[1] and is about 850 light-years (light travel distance) from Earth.[2][5]


WASP-121b - computer simulated views (August 2018)

WASP-121b is a "hot Jupiter" exoplanet with a mass about 1.18 times that of Jupiter and a radius about 1.81 times that of Jupiter.[4][5] The exoplanet orbits WASP-121, its host star, every 1.27 days.[4][5] Hot water molecules, and evidence for the presence of titanium(II) oxide (TiO) and vanadium(II) oxide (VO), have been found in the stratosphere of WASP-121b.[3] The upper atmosphere of the planet is heated to 2,500 °C (4,530 °F), hot enough to boil some metals.[5]

See also[edit]


  1. ^ a b Staff. "Finding the constellation which contains given sky coordinates". djm.cc. Retrieved 3 August 2017.
  2. ^ a b c d e Brown, A. G. A; et al. (2016). "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties". Astronomy and Astrophysics. 595. A2. arXiv:1609.04172. Bibcode:2016A&A...595A...2G. doi:10.1051/0004-6361/201629512.Gaia Data Release 1 catalog entry
  3. ^ a b c d e f g h i j k l m n o Staff (2015). "Planet WASP-121 b". exoplanet.eu. Retrieved 3 August 2017.
  4. ^ a b c d e f Staff (2017). "WASP Planets". wasp-planets.net. Retrieved 3 August 2017.
  5. ^ a b c d e f Landau, Elizabeth; Villard, Ray (2 August 2017). "Hubble Detects Exoplanet with Glowing Water Atmosphere". NASA. Retrieved 2 August 2017.
  6. ^ a b Evans, Thomas M.; et al. (2 August 2017). "An ultrahot gas-giant exoplanet with a stratosphere". Nature. 548: 58–61. arXiv:1708.01076. Bibcode:2017Natur.548...58E. doi:10.1038/nature23266. Retrieved 2 August 2017.

External links[edit]

Coordinates: Sky map 07h 10m 24.0s, −39° 05′ 51″