Retrieving Orbital and Interior Evolution Parameters of Giant Planets

The orbital evolution of a planet affects its interior through both the changing insolation onto its atmosphere and the deposition of tidal heating into the interior. As such, tidal circularization is of particular interest because it both affects observable orbital parameters and can temporarily inflate planets. Unfortunately, it is difficult to separate out tidal heating from composition differences and the anomalous heating typical of hot Jupiters. For this work, we have identified a small set of cool, eccentric giant planets which includes WASP-107 b and GJ 3470 b. Modelling their orbital and interior evolution jointly and applying a Bayesian statistical retrieval, we are able to constrain both the interior properties and the tidal Q. The resulting bulk metallicities are more reliable than previous work, and can help to explain the planets' slightly larger-than-expected radii and contextualize ongoing work studying their atmospheric abundances.