2019/10/11 by Samuel K. Grunblatt, Daniel Huber, Eric Gaidos +3 · 1 citation
Physics and Astronomy · #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/ab4c35
15 pages, 10 figures, accepted for publication in ApJ, please email [email protected] for complete machine-readable version of Table 1
arxiv created 2019/10/11 · arxiv updated 2020/01/08
Every Sun-like star will eventually evolve into a red giant, a transition which can profoundly affect the evolution of a surrounding planetary system. The timescale of dynamical planet evolution and orbital decay has important implications for planetary habitability, as well as post-main sequence star and planet interaction, evolution and internal structure. Here, we investigate these effects by estimating planet occurrence around 2476 low-luminosity red giant branch (LLRGB) stars observed by the NASA K2 mission. We measure stellar masses and radii using asteroseismology, with median random uncertainties of 3.7% in mass and 2.2% in radius. We compare this planet population to the known population of planets around dwarf Sun-like stars, accounting for detection efficiency differences between the stellar populations. We find that 0.51% +/- 0.29% of LLRGB stars host planets larger than Jupiter with orbital periods less than 10 days, tentatively higher than main sequence stars hosting similar planets (0.15% +/- 0.06%). Our results suggest that the effects of stellar evolution on the occurrence of close-in planets larger than Jupiter is not significant until stars have begun ascending substantially up the red giant branch (>~ 5-6 Rsun).