HAT-P-8b

HAT-P-8b
Size comparison of HAT-P-8b with Jupiter.
Discovery
Discovered byHATNet Project
Discovery dateDecember 5, 2008
Transit
Orbital characteristics
0.04496+0.00046
−0.00045 AU
Eccentricity<0.0060[1]
3.0763458±0.0000024[2] d
Inclination87.5+1.9
−0.9
StarGSC 02757-01152
Physical characteristics
1.334±0.013 RJ[3]
Mass1.354±0.035[1] MJ

HAT-P-8b is an extrasolar planet located approximately 720 light years away in the constellation of Pegasus, orbiting the 10th magnitude star GSC 02757-01152. This planet was discovered by transit on December 5, 2008. Despite the designation as HAT-P-8b, it is the 11th planet discovered by the HATNet Project. The mass of the planet is 50% more than Jupiter while the radius is also 50% more than Jupiter. The mass of this planet is exact since the inclination of the orbit is known, typical for transiting planets. This is a so-called “hot Jupiter” because this Jupiter-like gas giant planet orbits in a really close torch orbit around the star, making this planet extremely hot (in the order of a thousand kelvins). The distance from the star is roughly 20 times smaller than that of Earth from the Sun, which places the planet roughly 8 times closer to its star than Mercury is from the Sun. The “year” on this planet lasts only 3 days, 1 hour, 49 minutes, and 54 seconds, compared with Earth's 365 days, 6 hours, 9 minutes, and 10 seconds in a sidereal year.[4]

The study in 2012, utilizing a Rossiter–McLaughlin effect, have determined the planetary orbit is mildly misaligned with the rotational axis of the star, misalignment equal to -17+9.2
−11.5°.[5]

  1. ^ a b Cite error: The named reference Bonomo2017 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Mancini2013 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Wang2021 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Latham2009 was invoked but never defined (see the help page).
  5. ^ Albrecht, Simon; Winn, Joshua N.; Johnson, John A.; Howard, Andrew W.; Marcy, Geoffrey W.; Butler, R. Paul; Arriagada, Pamela; Crane, Jeffrey D.; Shectman, Stephen A.; Thompson, Ian B.; Hirano, Teruyuki; Bakos, Gaspar; Hartman, Joel D. (2012), "Obliquities of Hot Jupiter Host Stars: Evidence for Tidal Interactions and Primordial Misalignments", The Astrophysical Journal, 757 (1): 18, arXiv:1206.6105, Bibcode:2012ApJ...757...18A, doi:10.1088/0004-637X/757/1/18, S2CID 17174530