Planetary transit candidates in the CoRoT initial run: resolving their nature ^*,**

¹ Laboratoire d'Astrophysique de Marseille, 38 rue Frédéric Joliot-Curie, 13388 Marseille Cedex 13, France e-mail: Claire.Moutou@oamp.fr
² School of Physics, University of Exeter, Exeter, EX4 4QL, UK
³ IAP, 98bis boulevard Arago, 75014 Paris, France
⁴ Instituto de Astrofõsica de Canarias, 38205 La Laguna, Tenerife, Spain
⁵ LESIA, Obs de Paris, Place J. Janssen, 92195 Meudon Cedex, France
⁶ Research and ScientiPc Support Department, ESTEC/ESA, PO Box 299, 2200 AG Noordwijk, The Netherlands
⁷ Thüringer Landessternwarte, Sternwarte 5, Tautenburg 5, 07778 Tautenburg, Germany
⁸ Observatoire de l'Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, Switzerland
⁹ School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
¹⁰ Bern, Swtizerland
¹¹ Institut d'Astrophysique Spatiale, Université Paris XI, 91405 Orsay, France
¹² Observatório Nacional, Rio de Janeiro, RJ, Brazil
¹³ University of Vienna, Institute of Astronomy, Türkenschanzstr. 17, 1180 Vienna, Austria
¹⁴ Institute of Planetary Research, German Aerospace Center, Rutherfordstrasse 2, 12489 Berlin, Germany
¹⁵ Observatoire de la Côte d'Azur, Laboratoire Cassiopée, BP 4229, 06304 Nice Cedex 4, France
¹⁶ Space Research Institute, Austrian Academy of Science, Schmiedlstr. 6, 8042 Graz, Austria
¹⁷ University of Liège, Allée du 6 août 17, Sart Tilman, Liège 1, Belgium
¹⁸ Rheinisches Institut für Umweltforschung an der Universität zu Köln, Aachener Strasse 209, 50931, Germany
¹⁹ LUTH, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place Jules Janssen, 92195 Meudon, France

Received: 20 February 2009
Accepted: 4 May 2009

Abstract

With the release of CoRoT lightcurves of the Initial Run IRa01, 50 transiting planetary candidates have been published in a companion paper. About twenty of them were identified as binary stars from the CoRoT lightcurve itself. Complementary observations were conducted for 29 candidates, including ground-based photometry and radial-velocity measurements. Two giant planets were identified and fully characterized. Nineteen binaries are recognized, from which 10 are background eclipsing binaries in the CoRoT mask or triple systems, diluted by the main CoRoT target. Eight cases remain of unclear origin, one of them still being a planetary candidate. Comparison with simulations shows that the actual threshold of confirmed planet detection in this field does not yet fulfill the expectations, and a number of reasons are invoked, like the ranking process based on lightcurve analyses, and the strategy and limits of follow-up observations for targets fainter than magnitude 15.