'Homeless' planet without a star found

A "homeless" planet that is not orbiting a star and thus is free of any gravitation link has been discovered, Canadian and European astronomers are reporting. University of Montreal researchers and European colleagues said it is the first isolated planet of its kind ever to be observed. "Although theorists had established the existence of this type of very cold and young planet, one had never been observed until today," astrophysicist Etienne Artigau said in a University of Montreal release Wednesday. The planet dubbed CFBDSIR2149 is located within a group of very young stars known as the AB Doradus Moving Group but is not gravitationally linked to any of them and has the specific criteria of mass, temperature and age to be designated as a "planet." "Over the past few years, several objects of this type have been identified, but their existence could not be established without scientific confirmation of their age," Montreal doctoral student Jonathan Gagne said. "Astronomers weren't sure whether to categorize them as planets or as Brown dwarfs. Brown dwarfs are what we could call failed stars, as they never manage to initiate nuclear reactions in their centers." Researchers say the isolated planet, about seven times the size of Jupiter, could have been flung away from other bodies during its formation.