COROT is a mission led by the French Space Agency (CNES), with contributions from ESA, Austria, Belgium, Germany, Spain and Brazil. The craft has discovered a massive, planet-sized object orbiting its parent star closely, unlike anything ever spotted before. The find is so exotic scientists are unsure as to whether this oddity is actually a planet or a failed star. The object, named COROT-exo-3b, is about the size of Jupiter, but packs more than 20x the mass. It takes only 4 days and 6 hours to orbit its parent star, which is slightly larger than the Sun. COROT-exo-3b was found as the satellite observed the drop in the brightness of the star each time the object (COROT-exo-3b) passed in front.

"We were taken by surprise when we found this massive object orbiting so close to its parent star", said Dr. Magali Deleuil from the Laboratoire d'Astrophysique de Marseille (LAM), leader of the team that made the discovery. She added, "COROT-exo-3b is really unique - we’re still debating its nature." The search for planets with orbital periods less than 10 days orbiting close to the parent star has lasted almost 15 years. During this time, scientists have encountered planets with masses 12x that of Jupiter, and stars 70x as massive as Jupiter, but none in between. This is why the 20-Jupiter-mass COROT-exo-3b was such a surprise. This odd find does not fall into either conventional category of planets or brown dwarfs. A brown dwarf is a ‘failed star’, a sub-stellar object that is not undergoing nuclear fusion at its core, but displays some stellar characteristics. 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.