HD 188015 b

HD 188015 b is an extrasolar planet announced by the California and Carnegie Planet Search team in 2005.^[1] Like majority of known planets, it was discovered using the radial velocity method.

HD 188015 b

Discovery
Discovered by	Marcy et al.[1]
Discovery site	United States
Discovery date	January 25, 2005
Detection method	Doppler spectroscopy
Orbital characteristics
Apastron	1.368 AU (204,600,000 km)
Periastron	1.038 AU (155,300,000 km)
Semi-major axis	1.203 ± 0.070 AU (180,000,000 ± 10,500,000 km)
Eccentricity	0.137 ± 0.026
Orbital period (sidereal)	461.2 ± 1.7 d 1.263 y
Average orbital speed	28.47
Time of periastron	2,451,787 ± 17
Argument of periastron	222° ± 10
Semi-amplitude	37.6 ± 1.2
Star	HD 188015
Physical characteristics
Mass	>1.50 ± 0.13 MJ

The planet has a minimum mass of about 1.25 Jupiter masses. It orbits HD 188015 in a slightly eccentric orbit with a semi-major axis about 20% further than Earth's.

Stability analysis reveals that if Earth-sized planets existed at the Trojan points of HD 188015 b, their orbits would be stable for long periods of time.^[2]