[en] Of the over 400 known exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets, including the first terrestrial exoplanet (CoRoT-7b), have been discovered using a space mission designed to find smaller and more distant planets than can be seen from the ground. Here we report transit observations of CoRoT-9b, which orbits with a period of 95.274days on a low eccentricity of 0.11+/-0.04 around a solar-like star. Its periastron distance of 0.36 astronomical units is by far the largest of all transiting planets, yielding a `temperate' photospheric temperature estimated to be between 250 and 430K. Unlike previously known transiting planets, the present size of CoRoT-9b should not have been affected by tidal heat dissipation processes. Indeed, the planet is found to be well described by standard evolution models with an inferred interior composition consistent with that of Jupiter and Saturn.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Deeg, H. J.; Instituto de AstrofÃsica de Canarias, C. Via Lactea S/N, E-38205 La Laguna, Tenerife, Spain
Hidas, M.; Las Cumbres Observatory Global Telescope Network, Inc., 6740 Cortona Drive, Suite 102, Santa Barbara, California 93117, USA ; Sydney Institute for Astronomy, School of Physics, The University of Sydney, New South Wales 2006, Australia
Kabath, P.; Institute of Planetary Research, German Aerospace Center, Rutherfordstrasse 2, D-12489 Berlin, Germany ; Present addresses: European Southern Observatory Chile, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile (P.K.) ; Departamento de AstronomÃa y AstrofÃsica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile (M.R.).
Lammer, H.; Space Research Institute, Austrian Academy of Science, Schmiedlstrasse 6, A-8042 Graz, Austria
Rabus, M.; Department de AstrofÃsica, Universidad de La Laguna, E-38200 La Laguna, Tenerife, Spain ; Present addresses: European Southern Observatory Chile, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile (P.K.) ; Departamento de AstronomÃa y AstrofÃsica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile (M.R.).
Rauer, H.; Institute of Planetary Research, German Aerospace Center, Rutherfordstrasse 2, D-12489 Berlin, Germany ; Center for Astronomy and Astrophysics, TU Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany
Rouan, D.; LESIA, Observatoire de Paris, CNRS, Place J. Janssen, 92195 Meudon cedex, France
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