Coldest Star and Close Neighbor of the Sun Discovered

Using NASA's telescopes scientists have discovered a frosty brown dwarf star that is a close neighbor of the Sun.

Astronomers at Penn State University have discovered a brown dwarf star that is believed to be the coldest of its kind- as frosty as Earth's North Pole. Interestingly, this Brown Dwarf star, called the WISE J085510.83-071442, was found 7.2 light years away making it the fourth closest neighbor to our Sun.

The frosty neighbor was discovered with the help of NASA's Wide-field Infrared Survey Explorer (WISE) and Spitzer Space Telescopes.

"It is very exciting to discover a new neighbor of our solar system that is so close," said Kevin Luhman, an associate professor of astronomy and astrophysics at Penn State and a researcher in the Penn State Center for Exoplanets and Habitable Worlds. "In addition, its extreme temperature should tell us a lot about the atmospheres of planets, which often have similarly cold temperatures."

Though this find is exciting, sadly it is not a perfect location for human space travel in the distant future.

Brown dwarfs are known to kickstart their lives as stars in the form of withering bundles of gas. But these brown dwarfs do not have the mass to burn the nuclear fuel and emit starlight.  The newly found frosty neighbor has a chilly temperature that varies between minus 48 to minus 13 degree Celsius. 

Previous coldest brown dwarfs discovered, also using WISE, were close to room temperatures. 

"Any planets that might orbit it would be much too cold to support life as we know it" Luhman said.

"This object appeared to move really fast in the WISE data. That told us it was something special. The closer a body, the more it appears to move in images taken months apart. Airplanes are a good example of this effect: a closer, low-flying plane will appear to fly overhead more rapidly than a high-flying one."

The researchers were able to spot the new neighbor as WISE surveyed the complete sky twice in infrared light and some of the areas were even observed over three times.  The thermal glow of the cold brown dwarfs is seen only in infrared light.

It was in 2013, that the astronomers first noticed the intense motion of the new brown dwarf star, estimated to be 3-10 times the mass of Jupiter.  The astronomers confirmed it to be a brown dwarf and not a planet after observations of all its images.

"It is remarkable that even after many decades of studying the sky, we still do not have a complete inventory of the Sun's nearest neighbors," said Michael Werner, the project scientist for Spitzer at NASA's Jet Propulsion Laboratory (JPL), which manages and operates Spitzer. "This exciting new result demonstrates the power of exploring the universe using new tools, such as the infrared eyes of WISE and Spitzer."