HIRES/HARPS radial velocities for HAT-P-2

We study these types of tidal interactions in an eccentric Hot Jupiter called HAT-P-2b, which is a system where a long-period companion has been suggested and hints of orbital evolution were detected. Using 5 additional years of radial velocity (RV) measurements, we further investigate these phenomena.

We investigated the long-period companion by jointly fitting RVs and Hipparcos-Gaia astrometry and confirmed this long-period companion, significantly narrowed down the range of possible periods (P_2_=8500_-1500_^+2600^days), and determined that it must be a substellar object (10.7_-2.2_^+5.2^Mj). We also developed a modular pipeline to simultaneously model rapid orbital evolution and the long-period companion. We find that the rate and significance of evolution are highly dependent on the long-period companion modeling choices.