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Tidal Decay of Close Planetary Orbits

F. A. Rasio·C. A. Tout·S. H. Lubow·M. Livio
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Abstract

The 4.2-day orbit of the newly discovered planet around 51~Pegasi is formally unstable to tidal dissipation. However, the orbital decay time in this system is longer than the main-sequence lifetime of the central star. Given our best current understanding of tidal interactions, a planet of Jupiter's mass around a solar-like star could have dynamically survived in an orbit with a period as short as $\sim10\,$hr. Since radial velocities increase with decreasing period, we would expect to find those planets close to the tidal limit first and, unless this is a very unusual system, we would expect to find many more. We also consider the tidal stability of planets around more evolved stars and we re-examine in particular the question of whether the Earth can dynamically survive the red-giant phase in the evolution of the Sun.

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F. A. Rasio, C. A. Tout, S. H. Lubow, M. Livio. 1996-05-11. Tidal Decay of Close Planetary Orbits. https://doi.org/10.1086/177941

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