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

摘要

We present the discovery of three new giant planets around threemetal-deficient stars: HD5388b (1.96),HD181720b (0.37), andHD190984b (3.1). All the planets havemoderately eccentric orbits (ranging from0.26to0.57) and long orbital periods (from777 to4885days). Two of the stars (HD181720 andHD190984) were part of a program searching for giant planetsaround a sample of 100moderatelymetal-poor stars, while HD5388 was part of the volume-limitedsample of the HARPS GTOprogram. Our discoveries suggest thatgiant planets in long period orbits are not uncommon around moderatelymetal-poor stars. Key words: planets and satellites:formation - stars: abundances - stars: fundamental parameters -planetary systems - techniques: radial velocities - techniques:spectroscopic