The Equilibrium Temperature of Planets on Eccentric Orbits: Time Scales and Averages

Abstract From estimates of the near-surface heat capacity planets it is shown that thermal timescale larger than orbital period in presence a global ocean well-mixed to depth 100 m, or an atmosphere with pressure several tens bars. As consequence, temperature fluctuations such on eccentric orbits are damped. The average should be calculated by taking temporal mean irradiation over orbit, which increases 1 / − e 2 . This conclusion independent distance and valid for Sun-like stars; damping even stronger low-mass main sequence hosts.