NOWAK G., NIEDZIELSKI A., WOLSZCZAN A., ADAMOW M. and MACIEJEWSKI G.
Abstract (from CDS):
We report the discovery of planetary-mass companions to two red giants by the ongoing Penn State-ToruN Planet Search (PTPS) conducted with the 9.2 m Hobby-Eberly Telescope. The 1.1 M☉K0-giant, BD+15 2940, has a 1.1 MJ minimum mass companion orbiting the star at a 137.5 day period in a 0.54 AU orbit what makes it the closest–in planet around a giant and possible subject of engulfment as the consequence of stellar evolution. HD 233604, a 1.5 M☉K5-giant, is orbited by a 6.6 MJ minimum mass planet which has a period of 192 days and a semi-major axis of only 0.75 AU making it one of the least distant planets to a giant star. The chemical composition analysis of HD 233604 reveals a relatively high 7Li abundance which may be a sign of its early evolutionary stage or recent engulfment of another planet in the system. We also present independent detections of planetary-mass companions to HD 209458 and HD 88133, and stellar activity-induced radial velocity variations in HD 166435, as part of the discussion of the observing and data analysis methods used in the PTPS project.