Astronomers have found signs of water ice clouds on an object just 7.3 light-years from Earth - less than twice the distance of Alpha Centauri, the nearest star system to the sun. If confirmed, the discovery is the first sighting of water clouds beyond our solar system. The clouds shroud a Jupiter-sized object known as a brown dwarf and should yield insight into the nature of cool giant planets orbiting other suns.

 

Kevin Luhman, an astronomer at Pennsylvania State University, University Park, recently discovered the nearby object by using images from NASA’s WISE infrared space telescope, which scanned the sky from 2010 to 2011. A brown dwarf is a failed star and has so little mass that it can't sustain nuclear reactions, so after its birth it fades and cools. This brown dwarf, named WISE J0855-0714, is the coldest known. Its temperature is slightly below the freezing point of water, so it's colder than Earth's mean temperature but warmer than Jupiter’s.

 

The new neighbor resembles a giant planet—it's as large as Jupiter and three to 10 times as massive—but is solitary, which means it has no sun whose glare interferes with our view of it. Moreover, it's nearby: the fourth closest system to the sun, after Alpha Centauri, Barnard's star, and Luhman 16.

 

Still, because the object is small and cold, it's so dim that no ground-based observatory had seen it.

 

 

PHOTO: Exo Planet - Class M Earth-Like Planet image via Shutterstock