Pumping the Eccentricity of Exoplanets by Tidal Effect

A. C. M. Correia, G. Boué, J. Laskar

Abstract
Planets close to their host stars are believed to undergo significant tidal interactions, leading to a progressive damping of the orbital eccentricity. Here we show that when the orbit of the planet is excited by an outer companion, tidal effects combined with gravitational interactions may give rise to a secular increasing drift on the eccentricity. As long as this secular drift counterbalances the damping effect, the eccentricity can increase to high values. This mechanism may explain why some of the moderate close-in exoplanets are observed with substantial eccentricity values.

Keywords
celestial mechanics – planetary systems – planets and satellites: general

The Astrophysical Journal Letters
Volume 744, Page L23_1
January 2012

DOI: 10.1088/2041-8205/744/2/L23
ADS Bibliographic code: 2012ApJ...744L..23C