Guardians of the Stars
DENIS 0255-4700 is an extremely faint brown dwarf about 16 light years from the Solar System in the southern constellation of Eridanus. It is the closest known isolated L brown dwarf, and only after the binary Luhman 16. It is also the faintest brown dwarf (with the absolute magnitude of MV=24.44) having measured visible magnitude.
DENIS 0255-4700 was identified for the first time as a probable nearby object in 1999. Its proximity to the Solar System was established by the RECONS group in 2006 when its trigonometric parallax was measured. DENIS 0255-4700 has a relatively small tangential velocity of 27.0 ± 0.5 km/s.
The photospheric temperature of DENIS 0255-4700 is estimated at about 1300 K. Its atmosphere in addition to hydrogen and helium contains water vapor, methane and possibly ammonia. The mass of DENIS 0255-4700 lies in the range from 25 to 65 Jupiter masses corresponding to the age range from 0.3 to 10 billion years.