Gas Giants Orbiting HD 86950 and HD 222076

The Pan-Pacific Planet Search VI: Giant planets orbiting HD 86950 and HD 222076

Authors:

Wittenmyer et al

Abstract:

We report the detection of two new planets orbiting the K giants HD 86950 and HD 222076, based on precise radial velocities obtained with three instruments: AAT/UCLES, FEROS, and CHIRON. HD 86950b has a period of 1270±57 days at a=2.72±0.08 AU, and m sin i=3.6±0.7 Mjup. HD 222076b has P=871±19 days at a=1.83±0.03 AU, and m sin i=1.56±0.11 Mjup. These two giant planets are typical of the population of planets known to orbit evolved stars. In addition, we find a high-amplitude periodic velocity signal (K∼50 m/s) in HD 29399, and show that it is due to stellar variability rather than Keplerian reflex motion. We also investigate the relation between planet occurrence and host-star metallicity for the 164-star Pan-Pacific Planet Search sample of evolved stars. In spite of the small sample of PPPS detections, we confirm the trend of increasing planet occurrence as a function of metallicity found by other studies of planets orbiting evolved stars.