First rogue planet discovered


November 14, 2012

Artist’s impression of CFBDSIR2149, the rogue planet wandering through space roughly 100 light years from our solar system (Image: ESO/L. Calçada/P. Delorme/Nick Risinger ( Saito/VVV Consortium)

Artist’s impression of CFBDSIR2149, the rogue planet wandering through space roughly 100 light years from our solar system (Image: ESO/L. Calçada/P. Delorme/Nick Risinger ( Saito/VVV Consortium)

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While the Kepler spacecraft’s mission to discover Earth-like planets orbiting other stars continues to produce results, astronomers have found what is likely to be a planet that is not gravitationally bound to any star. The rogue planet, called CFBDSIR2149, is around 100 light years from our solar system, making it the closest free-floating planetary mass yet discovered. Its relative proximity, coupled with the lack of a bright star in its vicinity, has allowed researchers to study its atmosphere in great detail, which should help provide a better understanding of exoplanets that do orbit stars.

Without ties to any star, rogue planets, (also known as interstellar, free-floating, nomad or orphan planets), literally wander through space and are thought to form either as normal planets that are then ejected from their solar systems, or as lone objects like the smallest stars or brown dwarfs that have never been gravitationally tied to a star.

It is possible that rogue planets could be as numerous as normal stars and although objects that might be rogue planets have been found before, scientists were not able to be definitively categorize them as such without knowing their ages. This is because they may instead be “failed” stars called brown dwarfs, which lack the bulk to initiate nuclear reactions at their core to become a star.

The planet was discovered by astronomers using the European Southern Observatory’s (ESO) Very Large Telescope (VLT) in Chile and the Canada-France-Hawaii Telescope (CFHT) on Hawaii. After obtaining a series of infrared images of the planet using the CFHT, the VLT and its X-shooter spectrograph was used to deduce its mass, temperature and age.

The observations put the planet at between 50 and 120 million years old, with a temperature of roughly 400° C (752° F) and a mass four to seven times that of Jupiter. This ruled out the possibility of the object being a brown dwarf, which require a minimum mass 13 times that of Jupiter.

The movement of the planet, which was plotted by taking images at different times, suggests it is part of a nearby stream of young stars known as the AB Doradus Moving Group. This is the first time an isolated planetary mass object ever identified in a moving group.

“This group is unique in that it is made up of around thirty starts that all have the same age, have the same composition and that move together through space. It's the link between the planet and AB Doradus that enabled us to deduce its age and classify it as a planet,” said Lison Malo, an astrophysicist from the University of Montreal (UdeM).

The research team says the discovery of the rogue planet, which has been sought after for more than a decade, supports theories relating to the formation of stars and planets and adds credence to theories suggesting such objects could be more numerous than currently believed.

Source: ESO, UdeM

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

If it's not a star, but a planet, absolutely alone, where does it get its energy from? why is it 400 degrees centigrade and not in - 400 degree range.

Dawar Saify

Oh they're out there all right. Many more where this one came from. AND they're coming to get us. You can bet the farm on that!


Some astronomers can correct me if I'm wrong but large masses such as this rogue planet can generate heat internally from nuclear decay just as the Earth and Jupiter do. The mass in these cases are not large enough to start a nuclear fusion reaction to become a star.


This is a young object, still cooling off after it's formation.

Raimo Kangasniemi

Dawar. I think it's probably still hot from when it was formed. If it's only 100 million years old that's 1/46th the age of the Earth. It probably has a molten core with a relatively thin crust at this early age. But I'm not an Astrophysicist.


There are multiple sources of heat available the off the top of my head. Nuclear decay, gravitational compression, meteor impacts, if there is a moon tidal friction, and the odd bit of fusion from time to time.


Dose a planet get smaller when it cools off?


Rogue? Why this harsh terminology? Please explain exactly what recalcitrant behaviour this planet is accused of. Why has this planet been slandered in this way? Just like Pluto, the wretched thing is unable to defend itself. You astronomers are fast gaining a reputation for interstellar bigotry.


If a civilization wanted to engage in very-long-term interstellar travel, isn't this exactly the kind of modified natural object they'd want to use?

Bruce Duggan

I'd like to live there.....

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