Space.com is reporting that scientists at the Institute of Planetology and Astrophysics of Grenoble, France, have discovered a "rogue planet" -- that is to say a planet that is drifting in interstellar space, not as part of a star system.

The rogue planet was discovered by the Canada-France-Hawaii Telescope. The French scientists then examined the body's properties with the European Southern Observatory's Very Large Telescope in Chile.

Rogue planet a huge gas giant

The rogue planet, designated as CFBDSIR2149, is likely a gas giant about four to seven times the mass of Jupiter, according to Space.com. It currently resides about 100 light-years from Earth, very likely ejected in some manner from the star system where it is formed. It is part of the AB Doradus moving group of stars that formed between 50 million to 120 million years ago. There is the slight possibility, however, that CFBDSIR2149 is a brown dwarf, a star that proved to be too small to ignite.

CFBDSIR2149 is a hot world

The French scientists were able to detect CFBDSIR2149 through its infrared signature. They suspect that the planet has an average temperature of 806 degrees Fahrenheit. While this might seem counter-intuitive for any planet not associated with a star, a paper called "New Concept for Internal Heat Production in Hot Jupiter Exo-Planets" suggests that some internal processes, perhaps tidal dissipation, perhaps some sort of nuclear or thermonuclear reaction may explain why a body like CFBDSIR2149 would retain heat in interstellar space.

How rogue planets are formed

A 2005 article in Space.com suggests that planets become rogue when another object passes by them, disrupting their orbits just enough to cause them to slowly, but steadily escape from their original star system. Jupiter sized worlds, such as CFBDSIR2149, have been observed as having elliptical orbits in other star systems, making them susceptible to being ejected in such a manner. Jupiter, however, has a more circular orbit and has actually served to circularize the orbits of the other planets in the Solar System.

Rogue planets common

Space.com suggests that rogue planets may be even more common that those which orbit stars, by as much as 50 percent more. However, rogue planets the size of CFBDSIR2149 are likely rare, with planets ranging from Neptune-sized to Earth-sized far more common.

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Rogue Planet Larger Than Jupiter Discovered 100 Light-Years from Earth