Encounter with a rogue planet

Astronomers have discovered the closest and most convincing known example of a planet wandering through space without a parent star.

Candidate orphan planets have been found since the 1990s, but because no one knew their ages, researchers could not determine whether the objects were truly planets or were heavier, star-like bodies called brown dwarfs. But Philippe Delorme of the Institute of Planetology and Astrophysics in Grenoble, France, and his colleagues say that the newfound body, dubbed CFBDSIR2149, is the first orphan that seems to be associated with a stream of young stars, the AB Doradus moving group, of known age أ¢â‚¬â€‌ between 50 million and 120 million years.

The authors identified the object using data from the Canadaأ¢â‚¬â€œFrance Brown Dwarf Survey InfraRed, and suggest that it has a planet-like mass four to seven times that of Jupiter.