Tidal interactions of close-in extrasolar planets: The OGLE cases

¹ Institut für Geophysik und Meteorologie, Universität zu Köln, Albertus-Magnus-Platz, 50923 Köln, Germany e-mail: paetzold@geo.uni-koeln.de
² Deutsches Zentrum für Luft- und Raumfahrt, Institut für Planetenforschung, Rutherfordstraße 2, 12489 Berlin, Germany e-mail: heike.rauer@dlr.de

Received: 12 February 2004
Accepted: 7 July 2004

Abstract

Close-in extrasolar planets experience extreme tidal interactions with their host stars. This may lead to a reduction of the planetary radius and a spin-up of stellar rotation. Tidal interactions have been computed for a number of extrasolar planets in circular orbits within 0.06 AU, namely for OGLE-TR-56 b. We compare our range of the tidal dissipation value with two dissipation models from Sasselov ([CITE]) and conclude that our choices are equivalent to these models. However, applied to the planet OGLE-TR-56 b, we find in contrast to Sasselov ([CITE]) that this planet will spiral-in toward the host star in a few billion years. We show that the average and maximum value of our range of dissipation are equivalent to the linear and quadratic dissipation models of Sasselov ([CITE]). Due to limitations in the observational techniques, we do not see a possibility to distinguish between the two dissipation models as outlined by Sasselov ([CITE]). OGLE-TR-56 b may therefore not be well suited to serve as a test case for dissipation models. The probable existence of OGLE-TR-3 b at 0.02 AU and the discovery of OGLE-TR-113 b at 0.023 AU and OGLE-TR-132 b at 0.03 AU may also counter Sasselovs ([CITE]) assumption of a pile-up stopping boundary at 0.04 AU.