HAT-P-8b

HAT-P-8b

Exoplanet		List of exoplanets
300px Size comparison of HAT-P-8b with Jupiter.
Parent star
Star		GSC 02757-01152
Constellation		Pegasus
Right ascension	(α)	22h 52m 09.862s
Declination	(δ)	+35° 26′ 49.59″
Apparent magnitude	(mV)	10.17
Distance		750 ± 50 ly (230 ± 15 pc)
Orbital elements
Semi-major axis	(a)	0.0487 ± 0.00026 AU
Eccentricity	(e)	~0
Orbital period	(P)	3.07632 ± 0.000004 d
Orbital speed	(υ)	173 km/s
Inclination	(i)	87.5+1.9 −0.9°
Time of transit	(Tt)	2,454,437.67582 ± 0.00034 JD
Physical characteristics
Mass	(m)	1.52+0.18 −0.16 MJ
Radius	(r)	1.5+0.08 −0.06 RJ
Discovery information
Discovery date		December 5, 2008
Discoverer(s)		HATNet Project
Discovery method		Transit
Discovery status		Unpublished
Database references
Extrasolar Planets Encyclopaedia		data
SIMBAD		data
Exoplanet Archive		data
Open Exoplanet Catalogue		data

HAT-P-8b is an extrasolar planet located approximately 750 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.

See also

• HATNet Project

External links

Media related to at Wikimedia Commons