In case you're completely unfamiliar:

Rouge (nomadic/orphan/ETC) planets are, well, exactly what they sound like- planetary bodies which are not gravitationally bound to a parent star or system; instead revolving around galaxies themselves. These objects are believed to occur as a result of their having either been ejected from a parent system, or developing as a type of sub brown dwarf (objects that never quite attained enough mass to achieve fusion and become a star) that was never actually bound to any other object in the first place. Last week, a team of astrophysicists from the University of Montreal, reported the discovery of what they believe to be the first direct observation of such a planet.

The object in question; Planet "CFBDSIR2149" - which isn't even the entire designation for the object BTW- was found amongst a group of  relatively young stars (around 50-120 million years old) which make up a formation called the AB Doradus Moving group. The apparent planet's "close" proximity to our own, around 75 light years from Earth, and the fact that there isn't a nearby parent star obstructing our view with it's own intense glow, means researchers have actually been able to do a detailed analysis of the object's atmosphere.