HD 171238 b

HD 171238 b

Exoplanet		List of exoplanets
Parent star
Star		HD 171238
Constellation		Sagittarius
Right ascension	(α)	18h 34m 43.6733s
Declination	(δ)	–28° 04′ 20.328″
Apparent magnitude	(mV)	8.66
Distance		163.99±9.49 ly (50.28±2.91 pc)
Spectral type		G8V
Orbital elements
Semi-major axis	(a)	2.54±0.06 AU
Periastron	(q)	1.52 AU
Apastron	(Q)	3.56 AU
Eccentricity	(e)	0.4+0.061 −0.065
Orbital period	(P)	1523+40 −45 d (4.17+0.11 −0.12 y)
Argument of periastron	(ω)	47+9.9 −9.8°
Time of periastron	(T0)	5062±20 JD
Physical characteristics
Minimum mass	(m sin i)	2.6±0.15 MJ
Discovery information
Discovery date		August 11, 2009
Discoverer(s)		Segransan et al.
Discovery method		Radial velocity (CORALIE)
Discovery site		La Silla Observatory
Discovery status		Published
Other designations
HIP 91085 b
Database references
Extrasolar Planets Encyclopaedia		data
SIMBAD		data
Exoplanet Archive		data
Open Exoplanet Catalogue		data

HD 171238 b is an extrasolar planet which orbits the G-type main sequence star HD 171238, located approximately 164 light years away in the constellation Sagittarius. This planet has minimum mass two and a half times greater than Jupiter and orbits two times closer to the star than Jupiter to the Sun. However this planet orbits in an eccentric orbit, about two astronomical units difference between periastron and apastron distances. This planet was discovered in August 2009 by using the radial velocity method in La Silla Observatory, Chile.