Oldest brown dwarf

Brown dwarfs are "failed stars" that never formed large enough to produce the internal temperatures necessary for nuclear fusion, i.e., they never begin to shine conventionally. Two brown dwarfs with ages in excess of 10 billion years have been discovered in our galaxy by astronomers using NASA’s Wide-field Infrared Survey Explorer (WISE) and announced on 20 November 2013. The two brown dwarfs have surface temperatures of only 250–600 Celsius.