2008ApJ...677L.117F

The atmospheres of close-in extrasolar planets absorb most of the incident stellar radiation, advect this energy, then reradiate photons in preferential directions. Those photons carry away momentum, applying a force on the planet. Here we evaluate the resulting secular changes to the orbit, known as the Yarkovsky effect. For known transiting planets, typical fractional changes in semimajor axis are about 1% over their lifetime, but could be up to ∼5% for close-in planets such as OGLE-TR-56b or inflated planets such as TrES-4. We discuss the origin of the correlation between semimajor axis and surface gravity of transiting planets in terms of various physical processes, finding that radiative thrusters are too weak by about a factor of 10 to establish the lower boundary that causes the correlation.