  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).
