Research Note

Transit timing analysis of CoRoT-1b^*

¹ Institute of Planetary Research, DLR, Rutherfordstr. 2, 12489 Berlin, Germany e-mail: szilard.csizmadia@dlr.de
² Institut de Mécanique Céleste et de Calcul de Éphémérides, UMR 8028 du CNRS, 77 avenue Denfert-Rochereau, 75014 Paris, France
³ Laboratoire d'Astronomie de Lille, Université Lille 1, 1 impasse de l'observatoire, 59000 Lille, France
⁴ Laboratoire d'Astrophysique de Marseille, UMR 6110, CNRS/Université de Provence, 38 rue F. Joliot-Curie, 13388 Marseille, France
⁵ Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA
⁶ School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
⁷ Observatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, Switzerland
⁸ Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain
⁹ INAF – Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy
¹⁰ Institut d'Astrophysique Spatiale, Université Paris XI, 91405 Orsay, France
¹¹ Institut d'Astrophysique de Paris, Université Pierre & Marie Curie, 98bis Bd Arago, 75014 Paris, France
¹² LUTH, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France
¹³ Observatório Nacional, Rio de Janeiro, RJ, Brazil
¹⁴ University of Vienna, Institute of Astronomy, Türkenschanzstr. 17, 1180 Vienna, Austria
¹⁵ Thüringer Landessternwarte, Sternwarte 5, Tautenburg 5, 07778 Tautenburg, Germany
¹⁶ Research and Scientific Support Department, ESTEC/ESA, PO Box 299, 2200 AG Noordwijk, The Netherlands
¹⁷ Observatoire de la Côte d'Azur, Laboratoire Cassiopée, BP 4229, 06304 Nice Cedex 4, France
¹⁸ Space Research Institute, Austrian Academy of Science, Schmiedlstr. 6, 8042 Graz, Austria
¹⁹ Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
²⁰ University of Liège, Allée du 6 août 17, Sart Tilman, Liège 1, Belgium
²¹ Rheinisches Institut für Umweltforschung an der Universität zu Köln, Aachener Strasse 209, 50931 Köln, Germany
²² Center for Astronomy and Astrophysics, TU Berlin, Hardenbergstr. 36, 10623 Berlin, Germany
²³ 
LESIA, UMR 8109 CNRS, Observatoire de Paris, UVSQ, Université Paris-Diderot, 5 place J. Janssen, 92195 Meudon, France

Received: 12 March 2009
Accepted: 26 October 2009

Abstract

Context. CoRoT, the pioneer space-based transit search, steadily provides thousands of high-precision light curves with continuous time sampling over periods of up to 5 months. The transits of a planet perturbed by an additional object are not strictly periodic. By studying the transit timing variations (TTVs), additional objects can be detected in the system.

Aims. A transit timing analysis of CoRoT-1b is carried out to constrain the existence of additional planets in the system.


Methods. We used data obtained by an improved version of the CoRoT data pipeline (version 2.0). Individual transits were fitted to determine the mid-transit times, and we analyzed the derived O–C diagram. N-body integrations were used to place limits on secondary planets.

Results. No periodic timing variations with a period shorter than the observational window (55 days) are found. The presence of an Earth-mass Trojan is not likely. A planet of mass greater than ~1 Earth mass can be ruled out by the present data if the object is in a 2:1 (exterior) mean motion resonance with CoRoT-1b. Considering initially circular orbits: (i) super-Earths (less than 10 Earth-masses) are excluded for periods less than about 3.5 days; (ii) Saturn-like planets can be ruled out for periods less than about 5 days; (iii) Jupiter-like planets should have a minimum orbital period of about 6.5 days.