Astronomy:HAT-P-8b
 Size comparison of HAT-P-8b with Jupiter. | |
| Discovery | |
|---|---|
| Discovered by | HATNet Project |
| Discovery date | December 5, 2008 |
| Transit | |
| Orbital characteristics | |
| 0.04496+0.00046 −0.00045 AU | |
| Eccentricity | <0.0060[1] |
| Orbital period | 3.0763458±0.0000024[2] d |
| Inclination | 87.5+1.9−0.9 |
| Star | GSC 02757-01152 |
| Physical characteristics | |
| Mean radius | 1.334±0.013 |♃|J}}}}}}[3] |
| Mass | 1.354±0.035[1] |♃|J}}}}}} |
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]
References
- ↑ 1.0 1.1 Bonomo, A. S. et al. (2017). "The GAPS Programme with HARPS-N at TNG . XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets". Astronomy and Astrophysics 602: A107. doi:10.1051/0004-6361/201629882. Bibcode: 2017A&A...602A.107B.
- ↑ Mancini, L. et al. (2013). "A lower radius and mass for the transiting extrasolar planet HAT-P-8 b". Astronomy and Astrophysics 551: A11. doi:10.1051/0004-6361/201220291. Bibcode: 2013A&A...551A..11M. https://www.aanda.org/articles/aa/full_html/2013/03/aa20291-12/aa20291-12.html.
- ↑ Wang, Xian-Yu et al. (1 July 2021). "Transiting Exoplanet Monitoring Project (TEMP). VI. The Homogeneous Refinement of System Parameters for 39 Transiting Hot Jupiters with 127 New Light Curves". The Astrophysical Journal Supplement Series 255 (1): 15. doi:10.3847/1538-4365/ac0835. Bibcode: 2021ApJS..255...15W.
- ↑ Latham, David W. et al. (2009). "Discovery of a Transiting Planet and Eight Eclipsing Binaries in HATNet Field G205". The Astrophysical Journal 704 (2): 1107–1119. doi:10.1088/0004-637X/704/2/1107. Bibcode: 2009ApJ...704.1107L.
- ↑ Albrecht, Simon; Winn, Joshua N.; Johnson, John A.; Howard, Andrew W.; Marcy, Geoffrey W.; Butler, R. Paul; Arriagada, Pamela; Crane, Jeffrey D. et al. (2012), "Obliquities of Hot Jupiter Host Stars: Evidence for Tidal Interactions and Primordial Misalignments", The Astrophysical Journal 757 (1): 18, doi:10.1088/0004-637X/757/1/18, Bibcode: 2012ApJ...757...18A
External links
- "HAT-P-8b light curve using differential photometry". Exoplanets. http://www.perseus.gr/Astro-Photometry-HAT-P-8-20090827.htm.
- "HAT-P-8 b". Exoplanets. http://media4.obspm.fr/exoplanets/base/planete.php?etoile=HAT-P-8&planete=b.
Coordinates: 
22h 52m 09.862s, +35° 26′ 49.59″
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