DENIS 0255−4700

DENIS 0255−4700 is an extremely faint brown dwarf from the Solar System in the southern constellation of Eridanus. It is the closest isolated L-type brown dwarf, and only after the binary Luhman 16. It is also the faintest brown dwarf having measured visible magnitude. A number of nearer T and Y-type dwarfs are known, specifically WISE 0855−0714, Epsilon Indi B and C, SCR 1845-6357 B, and UGPS 0722−05.

History of observations

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. The discovery of DENIS 0255-4700 was made by a photometric selection performed by Xavier Delfosse using the DENIS survey and optical spectroscopic reconnaissance observations obtained with Low-Resolution Imaging Spectrograph at the Keck II telescope in Mauna Kea observatory on December 23, 1998 by Eduardo L Martín and colleagues.

Properties

The photospheric temperature of DENIS 0255−4700 is estimated at 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. The brown dwarf is rotating rapidly with the period of 1.7 hours, and its rotational axis is inclined 40 degrees from the line-of-sight.