The HARPS search for southern extra-solar planets. XXXVII. Five new long-period giant planets and a system update

We describe radial-velocity time series obtained by HARPS on the 3.60 m telescope in La Silla (ESO, Chile) over ten years and report the discovery of five new giant exoplanets in distant orbits; these new planets orbit the stars HD 564, HD 30669, HD 108341, and BD -114672. Their periods range from 492 to 1684 days, semi-major axes range from 1.2 to 2.69 AU, and eccentricities range from 0 to 0.85. Their minimum mass ranges from 0.33 to 3.5 M_Jup. We also refine the parameters of two planets announced previously around HD 113538, based on a longer series of measurements. The planets have a period of 663 ± 8 and 1818 ± 25 days, orbital eccentricities of 0.14 ± 0.08 and 0.20 ± 0.04, and minimum masses of 0.36 ± 0.04 and 0.93 ± 0.06 M_Jup. Finally, we report the discovery of a new hot-Jupiter planet around an active star, HD 103720; the planet has a period of 4.5557 ± 0.0001 days and a minimum mass of 0.62 ± 0.025 M_Jup. We discuss the fundamental parameters of these systems and limitations due to stellar activity in quiet stars with typical 2 m s^-1 radial velocity precision.

Based on observations made with the HARPS instrument on the ESO 3.6 m telescope at La Silla (Chile), under the GTO program ID 072.C-0488, 183.C-0972 and the regular programs: 085.C-0019, 087.C-0831, 089.C-0732, 090.C-0421, 091.C-0034, and 092.C-0721.Figures 8 and 9 and Tables 4-9 are available in electronic form at http://www.aanda.org