Extrasolar planets and brown dwarfs around A–F type stars ^*,**,***

V. A planetary system found with HARPS around the F6IV–V star HD 60532

¹ Laboratoire d'Astrophysique de Grenoble, UMR 5571 CNRS, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 9, France e-mail: morgan.desort@obs.ujf-grenoble.fr
² Observatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, Switzerland
³ European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile

Received: 22 May 2008
Accepted: 22 September 2008

Abstract

Aims. In the framework of the search for extrasolar planets and brown dwarfs around early-type stars, we present the results obtained for the F-type main-sequence star HD 60532 (F6V) with HARPS.

Methods. Using 147 spectra obtained with HARPS at La Silla on a time baseline of two years, we studied the radial velocities of this star.

Results. HD 60532 radial velocities are periodically variable, and the variations have a Keplerian origin. This star is surrounded by a planetary system of two planets with minimum masses of 1 and 2.5 M_Jup and orbital separations of 0.76 and 1.58 AU, respectively. We also detect high-frequency, small-amplitude (10 m s^-1 peak-to-peak) pulsations. Dynamical studies of the system point toward a possible 3:1 mean-motion resonance that should be confirmed within the next decade.