The Pan-Pacific Planet Search III: five companions orbiting giant stars

We report a new giant planet orbiting the K giant HD 155233, as well as four stellar-mass companions from the Pan-Pacific Planet Search, a Southern hemisphere radial velocity survey for planets orbiting nearby giants and sub-giants. We also present updated velocities and a refined orbit for HD 47205b (7 CMa b), the first planet discovered by this survey. HD 155233b has a period of 885 ± 63 d, eccentricity e = 0.03 ± 0.20, and m sin I = 2.0 ± 0.5 M_Jup. The stellar-mass companions range in m sin I from 0.066 to 0.33 M_⊙. Whilst HD 104358B falls slightly below the traditional 0.08 M_⊙ hydrogen-burning mass limit, and is hence a brown-dwarf candidate, we estimate only a 50 per cent a priori probability of a truly sub-stellar mass.