Examining Planet-Star Interactions in HAT-P-2 b to Understand Stellar Pulsations and Hot Jupiters’ Migration

The role of planet-star interactions in stellar pulsations and in the inward migration of Hot Jupiters is not well understood. One possible migration mechanism proposed is that high-eccentricity gas giants experience tidal interactions with their host star that cause them to lose orbital energy and migrate to a close-in orbit.

Here, we study these types of tidal interactions in an eccentric Hot Jupiter called HAT-P-2 b, which is the first system where planet-induced tidal pulsations in a host star were measured and a trend in orbital parameters was found. An additional three years of RV measurements were taken by the California Planet Search (CPS) team on HIRES and 10 new transits of HAT-P-2b have also been observed with TESS. In this talk, we will discuss our pipeline that has confirmed a rapid change argument of periastron (ω) and eccentricity (e) from the CPS observations. These orbital parameter changes are significantly larger than what would be expected from general relativity alone and this rapid orbital evolution could be explained by tidal planet-star interactions. Thus, we will also discuss our models of the tidal pulsations observed in the star using MESA and GYRE and how these tidal pulsations relate to the rapid orbital evolution seen in HAT-P-2 b.