On the thermal bulge of a rotating hot Jupiter

It has been a longstanding puzzle as to why hot Jupiters are larger than they ought to be. Based on the scaling relationship derived from "equilibrium" thermal tides, the statistical analysis by Thorngren & Fortney (2017) disfavors the model because the resulting tidal dissipation is too strong. The result calls for a more comprehensive study of dynamical thermal tides. We follow the dynamical model by Arras & Socrates (2010) but take into account planetary rotation. We find that the thermal bugle of a rotating hot Jupiter is predominated by Rossby waves rather than rotationally modified g-modes of lower orders. This suggests that rotating hot Jupiters are less asynchronous than those inferred from the scaling relationship, thus weakening the tidal dissipation and alleviating the tension between the model and observations.

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