C. Moutou, M. Mayor, G. Lo Curto, S. Udry, F. Bouchy, W. Benz, C. Lovis, D. Naef, F. Pepe, N. C. Santos

Abstract
We report the discovery of six new substellar companions of main-sequence stars, detected by multiple Doppler measurements with the instrument HARPS installed on the ESO 3.6 m telescope, La Silla, Chile. These extrasolar planets orbit the stars BD-17 0063, HD20868, HD73267, HD131664, HD145377, and HD153950. The orbital characteristics that reproduce the observed data are presented, as well as the stellar and planetary parameters. Masses of the companions range from 2 to 18 Jupiter masses, and periods range from 100 to 2000 days. The observational data are carefully analysed for activity-induced effects, and we conclude that the observed radial velocity variations are of exoplanetary origin. Of particular interest is the very massive planet (or brown-dwarf companion) orbiting the metal-rich HD131664 with m₂ sin i = 18.15 M_Jup and a 5.34-year orbital period. These new discoveries are consistent with the observed statistical properties of exoplanet samples known so far.

Keywords
stars: planetary systems, techniques: radial velocities, techniques: spectroscopic, stars:, general

Astronomy & Astrophysics
Volume 496, Number 2, Page 513
2009 March

>> ADS>> DOI