Description: 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. 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.
Mass (Jupiter mass): 1.28 MJ
Radius (Jupiter radius): 1.4 RJ
Density: 0.568 g/cm³
Equilibrium Temperature: 1700.0 K
Orbital Period: 3.07634 days
Semi-major Axis: 0.04496 AU
Eccentricity: Unknown
Inclination: 87.8°
Host Star: HAT-P-8
Spectral Type: F6
Temperature: 6200.0 K
Stellar Mass: 1.27 M☉
Stellar Radius: 1.57 R☉
Planet Letter: b
Object ID: 3.11027
Host ID: 2.103446
Discovery Date: 2009-10
Discovery Year: 2008
Discovery Method: Transit
Discovery Locale: Ground
Discovery Facility: HATNet
Discovery Instrument: 2K CCD Sensor