U.S. astronomer has discovered WISE J085510.83-071442.5, the fourth closest system to our Sun and the coldest brown dwarf yet seen in the known Universe.
WISE 0855-0714 is estimated to be 3 to 10 times the mass of Jupiter and has a chilly temperature between minus 48 to minus 13 degrees Celsius.
With such a low mass, the object could be a gas giant that was ejected from its star system. But astronomers estimate WISE 0855-0714 is probably a brown dwarf rather than a planet since brown dwarfs are known to be fairly common.
At a distance of about 7.2 light-years away from Earth, this object is the fourth closest system to us, after Alpha Centauri AB – Proxima Centauri, Barnard’s Star and WISE 1049-5319 (also known as Luhman 16AB).
“It is very exciting to discover a new neighbor of our Solar System that is so close. In addition, its extreme temperature should tell us a lot about the atmospheres of planets, which often have similarly cold temperatures,” said Dr Kevin Luhman from the Pennsylvania State University, the author of a paper published in the Astrophysical Journal Letters (arXiv.org version).
“This object appeared to move really fast in the data from NASA’s Wide-field Infrared Survey Explorer (WISE). That told us it was something special.”
WISE was able to spot WISE 0855-0714 because it surveyed the entire sky twice in infrared light, observing some areas up to three times. Cool objects like brown dwarfs can be invisible when viewed by visible-light telescopes, but their thermal glow stands out in infrared light.
Reference: K.L. Luhman. 2014. Discovery of a ~250 K Brown Dwarf at 2 pc from the Sun.ApJ 786, L18; doi: 10.1088/2041-8205/786/2/L18