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WASP-121b 01.jpg
Artist's impression of WASP-121b and its host star
Discovery date2015[1]
Primary Transit[1]
Orbital characteristics
0.02544 AU (3,806,000 km)
1.275[1] d
Physical characteristics
Mean radius
1.81[2] RJ
Mass1.184[1][2] MJ

WASP-121b is an extrasolar planet orbiting the star WASP-121.[3][4] 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).[3][4] WASP-121b is in the constellation Puppis,[5] and is about 850 light-years (light travel distance) from Earth.[6][3][7]


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.[2][3] The exoplanet orbits WASP-121, its host star, every 1.27 days.[2][3] 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.[1] The upper atmosphere of the planet is heated to 2,500 °C (4,530 °F), hot enough to boil some metals.[3]

See also[edit]


  1. ^ a b c d e f g Staff (2015). "Planet WASP-121 b". exoplanet.eu. Retrieved 3 August 2017.
  2. ^ a b c d Staff (2017). "WASP Planets". wasp-planets.net. Retrieved 3 August 2017.
  3. ^ 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.
  4. ^ 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.
  5. ^ Staff. "Finding the constellation which contains given sky coordinates". djm.cc. Retrieved 3 August 2017.
  6. ^ 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
  7. ^ Greicius, Tony (7 August 2018). "Water Is Destroyed, Then Reborn in Ultrahot Jupiters". NASA. Retrieved 15 November 2018.

External links[edit]

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