The transiting exoplanet CoRoT-11b and its peculiar tidal evolution

¹ Research and Scientific Support Department, European Space Agency, PO Box 299, Keplerlaan 1, 2200 AG Noordwijk, The Netherlands
[davide.gandolfi@esa.int]
² Thüringer Landessternwarte, Sternwarte 5, Tautenburg, D-07778 Tautenburg, Germany
³ INAF-Osservatorio Astrofisico di Catania, Via Santa Sofia 78, I-95123 Catania, Italy

Abstract

CoRoT-11b is a fairly massive hot-Jupiter (M_p = 2.33 ± 0.34 M_Jup ) in a 3 days orbit around a F6 V star with an age of 2 ± 1 Gyr. The relatively high projected rotational velocity of the star (v sin i_⋆ = 40 ± 5 km/s) places CoRoT-11 among the most rapidly rotating planet hosting stars discovered so far. Assuming that the star is seen equator-on, the v sin i_⋆ and the star radius (R_∗ = 1.37±0.03 R_⊙) translate into a stellar rotation period of 1.73±0.26 days. This peculiar planet/star configuration offers an unique opportunity to study the tidal evolution of the system. Owing to the strong tidal interaction, the planet would have moved outwards, from a starting semi-major axis corresponding to an orbital period almost synchronized with the stellar rotation. We found that the present value of the tidal quality factor Q′_s could be measured by a timing of the mid-epoch of the transits to be observed with an accuracy of about 0.5 − 1 seconds over a time baseline of about 25 years.