The HARPS search for southern extra-solar planets. XXI. Three new giant planets orbiting the metal-poor stars HD 5388, HD 181720, and HD 190984

We present the discovery of three new giant planets around three metal-deficient stars: HD 5388 b (1.96 M_Jup), HD 181720 b (0.37 M_Jup), and HD 190984 b (3.1 M_Jup). All the planets have moderately eccentric orbits (ranging from 0.26 to 0.57) and long orbital periods (from 777 to 4885 days). Two of the stars (HD 181720 and HD 190984) were part of a program searching for giant planets around a sample of ~100 moderately metal-poor stars, while HD 5388 was part of the volume-limited sample of the HARPS GTO program. Our discoveries suggest that giant planets in long period orbits are not uncommon around moderately metal-poor stars.

Based on observations collected at the La Silla Parana Observatory, ESO (Chile) with the HARPS spectrograph at the 3.6-m telescope (ESO runs ID 72.C-0488 and 082.C-0212).Tables 3-5 (with the radial-velocities) are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/512/A47