2007A&A...470..721N

The HARPS high-resolution high-accuracy spectrograph was made available to the astronomical community in the second half of 2003. Since then, we have been using this instrument for monitoring radial velocities of a large sample of Solar-type stars (≃1400 stars) in order to search for their possible low-mass companions. Amongst the goals of our survey, one is to significantly increase the number of detected extra-solar planets in a volume-limited sample to improve our knowledge of their orbital elements distributions and thus obtain better constraints for planet-formation models. Radial-velocities were obtained from high-resolution HARPS spectra via the cross-correlation method. We then searched for Keplerian signals in the obtained radial-velocity data sets. Finally, companions orbiting our sample stars were characterised using the fitted orbital parameters. In this paper, we present the HARPS radial-velocity data and orbital solutions for 3 Solar-type stars: HD100777, HD190647, and HD221287. The radial-velocity data of HD100777 is best explained by the presence of a 1.16M_Jup planetary companion on a 384-day eccentric orbit (e=0.36). The orbital fit obtained for the slightly evolved star HD190647 reveals the presence of a long-period (P=1038d) 1.9M_Jup planetary companion on a moderately eccentric orbit (e=0.18). HD221287 is hosting a 3.1M_Jup planet on a 456-day orbit. The shape of this orbit is not very well-constrained because of our non-optimal temporal coverage and because of the presence of abnormally large residuals. We find clues that these large residuals result from spectral line-profile variations probably induced by processes related to stellar activity.