Presentation #216.04 in the session “Exoplanets and Systems: Giant Planet Atmospheres 3”.
The unexpectedly large radii of hot Jupiters is an open question in exoplanetary science for which a large number of explanations have been proposed. We leverage the strong relationship between hot Jupiter radii and incident fluxes to test these hypotheses by examining whether planets inflate as their parent stars brighten along the main sequence. To do this, we first study how the various observable parameters of the system can be used to predict the planetary radius. Next we show that stellar brightening is sufficient to cause detectable reinflation. We then argue that the predictors of radius, especially fractional age, flux, and ZAMS flux, point towards rapid reinflation that keeps pace with stellar brightening. We also find evidence for a delayed cooling effect in the first few gigayears of a planet’s life, though it is not sufficient alone to explain the inflation phenomenon. Finally, we identify a negative relationship between stellar metallicity and planet radius (corrected for mass and flux), likely as a result of higher planetary metallicities.