‘Orphan’ Alien Planet Found Nearby Without Parent Star
Astronomers have discovered a potential “rogue” alien planet wandering alone just 100 light-years from Earth, suggesting that such starless worlds may be extremely common across the galaxy.
Image: This artist’s impression shows the free-floating planet CFBDSIR2149, at 100 light-years away the closest such “rogue” world to our own solar system. It does not orbit a star and hence does not shine by reflected light; the faint glow it emits can only be detected in infrared light. Credit: ESO/L. Calçada/P. Delorme/Nick Risinger (skysurvey.org)/R. Saito/VVV Consortium
The free-floating object, called CFBDSIR2149, is likely a gas giant planet four to seven times more massive than Jupiter, scientists say in a new study unveiled today (Nov. 14). The planet cruises unbound through space relatively close to Earth (in astronomical terms), perhaps after being booted from its own solar system.
“If this little object is a planet that has been ejected from its native system, it conjures up the striking image of orphaned worlds, drifting in the emptiness of space,” study leader Philippe Delorme, of the Institute of Planetology and Astrophysics of Grenoble in France, said in a statement.
Orphan planet, or something else?
Delorme and his team discovered CFBDSIR2149 using the Canada-France-Hawaii Telescope, then examined its properties with the European Southern Observatory’s Very Large Telescope in Chile.
The newfound object appears to be among a stream of young stars called the AB Doradus moving group, the closest such stream to our own solar system.
Scientists think the AB Doradus stars all formed together between 50 million and 120 million years ago. If CFBDSIR2149 is indeed associated with the group — and researchers cite a nearly 90 percent probability — then the object is similarly young.
And if the discovery team is right about CFBDSIR2149’s age, the body is likely a planet, with an average temperature of 806 degrees Fahrenheit (430 degrees Celsius), researchers said.
There’s still a slight chance that CFBDSIR2149 is a brown dwarf — a strange object that’s larger than a planet but too small to trigger the internal nuclear fusion reactions required to become a full-fledged star. Additional observations should help decide the matter.
“We need new observations to confirm that this object belongs to the AB Doradus moving group,” Delorme told SPACE.com via email. “With a good distance measurement and a more accurate proper motion, we will be able to increase (or decrease) the probability that it is indeed a planet.”
The new study was published today in the journal Astronomy & Astrophysics.