The Rossiter-McLaughlin effect of CoRoT-3b and HD 189733b ^*,**

¹ Observatoire de l'Université de Genève, Chemin des Maillettes 51, 1290 Sauverny, Switzerland e-mail: Amaury.Triaud@unige.ch
² Institut d'Astrophysique de Paris, CNRS UMR 7095, Université Pierre & Marie Curie, 98bis boulevard Arago, 75014 Paris, France
³ Observatoire de Haute-Provence, CNRS USR 2207, 04879 St Michel de l'Observatoire, France
⁴ Laboratoire d'Astrophysique de Marseille, CNRS UMR 6110, Traverse du Siphon, 13376 Marseille, France
⁵ School of Physics & Astronomy, University of St Andrews, North Haugh, KY16 9SS, St Andrews, Fife, Scotland, UK
⁶ Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
⁷ Physikalisches Institut Universität Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
⁸ Observatoire de la Côte d'Azur, Laboratoire Cassiopée, CNRS UMR 6202, BP 4229, 06304 Nice Cedex 4, France

Received: 20 February 2009
Accepted: 5 July 2009

Abstract

We present radial-velocity sequences acquired during three transits of the exoplanet HD 189733b and one transit of CoRoT-3b. We applied a combined Markov-chain Monte-Carlo analysis of spectroscopic and photometric data on these stars, to determine a full set of system parameters including the projected spin-orbit misalignment angle of HD 189733b to an unprecedented precision via the Rossiter-McLaughlin effect: . This small but non-zero inclination of the planetary orbit is important to understand the origin of the system. On CoRoT-3b, results seem to point towards a non-zero inclination as well with , but this remains marginal. Systematic effects due to non-Gaussian cross-correlation functions appear to be the main cause of significant residuals that prevent an accurate determination of the projected stellar rotation velocity for both stars.