"COROT-exo-3b might turn out to be a rare object found by sheer luck", said Dr Francois Bouchy, from Institut d'Astrophysique de Paris (IAP), member of the team that made the discovery. “But it might just be a member of a new-found family of very massive planets that encircle stars more massive than our Sun. We’re now beginning to think that the more massive the star, the more massive the planet," he said.

Team member Dr Hans Deeg, of the Instituto de Astrofisica de Canarias (IAC), explains why this new object is such an important find for planet hunters, "It has puzzled us; we’re not sure where to draw the boundary between planets and brown dwarfs.”

As a planet, COROT-exo-3b would be the most massive and the densest found to date - more than twice as dense as lead. Studying it will help them better understand how to categorise such objects. The team also wants to understand how such a massive object formed so close to its parent.

Notes for editors:

This discovery of COROT-exo-3b was supported by a number of ground-based observations that made use of a network of observatories operated by different institutes worldwide. The telescope of Observatoire de Haute Provence (France) studied the object’s mass, orbit and stellar properties; the European Southern Observatory telescopes at Paranal and La Silla (Chile), looked into the properties of its parent star; the Thuringia State Observatory in Tautenburg (Germany) was used to help determining the object’s mass and orbit; the Canada-France-Hawaii Telescope on Mauna Kea looked for signals from faint stars in the vicinity; the Swiss Euler Telescope at La Silla (Chile) helped determine its mass and orbit; the Wise Observatory (Israel), the ESA telescope on Mt. Teide, Tenerife, and the telescope of the Astrophysical Institute of the Canary Islands were used to exclude signal contributions from other stars.

The results are due to appear in ‘Transiting exoplanets from the COROT space mission, VI. COROT-exo-3b: The first secure inhabitant of the Brown-dwarf desert’ by M. Deleuil et al, in the journal Astronomy and Astrophysics.

COROT is a mission led by the French Space Agency (CNES), with contributions from ESA, Austria, Belgium, Germany, Spain and Brazil. It was launched in December 2006. It carries a 27-cm aperture telescope designed to detect tiny changes in brightness from nearby stars. The mission’s main objectives are to search for exoplanets and to study stellar interiors.

For more information:

Magali Deleuil, Laboratoire d'astrophysique de Marseille
Email: Magali.Deleuil @ oamp.fr

Malcolm Fridlund, ESA COROT Project Scientist
Email: Malcolm.Fridlund @ esa.int