# Inflating and Deflating Hot Jupiters: Coupled Tidal and Thermal Evolution of Known Transiting Planets - Astrophysics > Earth and Planetary Astrophysics

Inflating and Deflating Hot Jupiters: Coupled Tidal and Thermal Evolution of Known Transiting Planets - Astrophysics > Earth and Planetary Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We examine the radius evolution of close-in giant planets with a planetevolution model that couples the orbital-tidal and thermal evolution. For 45transiting systems, we compute a large grid of cooling-contraction pathsforward in time, starting from a large phase space of initial semi-major axesand eccentricities. Given observational constraints at the current time for agiven planet semi-major axis, eccentricity, and system age we find possibleevolutionary paths that match these constraints, and compare the calculatedradii to observations. We find that tidal evolution has two effects. First,planets start their evolution at larger semi-major axis, allowing them tocontract more efficiently at earlier times. Second, tidal heating cansignificantly inflate the radius when the orbit is being circularized, but thiseffect on the radius is short-lived thereafter. Often circularization of theorbit is proceeded by a long period while the semi-major axis slowly decreases.Some systems with previously unexplained large radii that we can reproduce withour coupled model are HAT-P-7, HAT-P-9, WASP-10, and XO-4. This increases thenumber of planets for which we can match the radius from 24 of 45 to as manyas 35 for our standard case, but for some of these systems we are required tobe viewing them at a special time around the era of current radius inflation.This is a concern for the viability of tidal inflation as a general mechanismto explain most inflated radii. Also, large initial eccentricities would haveto be common. We also investigate the evolution of models that have a floor onthe eccentricity, as may be due to a perturber. In this scenario we match theextremely large radius of WASP-12b. Abridged

Author: ** N. Miller UCSC, J. J. Fortney UCSC, B. Jackson NASA Goddard**

Source: https://arxiv.org/