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2M12072M1207 or 2MASSWJ 1207334-393254 is a brown dwarf star located at right ascension 12 hrs, 7 minutes, 33.4 seconds, and declination -39 degrees, 32 minutes, and 54 seconds (J2000.0 celestial coordinates). This particular substellar object was discovered during the course of the 2MASS infrared sky survey: hence the "2M" in its name, followed by its celestial coordinates. It is roughly 70 parsecs away, in the constellation Centaurus; with a fairly early (for a brown dwarf) spectral type of M8, it is very young, and a likely member of the TW Hydrae association. Its estimated mass is 25 Jupiter masses. This system is noteworthy for containing the first known extrasolar planet (or exoplanet) to be discovered around a brown dwarf, as well as arguably being the first exoplanet ever directly imaged. It has been imaged by ESO and [1] the HST. Observations by the HST in particular have greatly strengthened the case for the system, by indicating that both objects share a common proper motion. Provisionally named 2M1207 b, the gas giant planet is, like its primary, very hot; the estimated surface temperature is roughly 1250 K. The planet's mass is about five times that of Jupiter, well below the calculated limit for deuterium fusion in brown dwarfs, which is 10-13 Jupiter masses. Needless to say, the planet is not a likely candidate to support life, neither on its surface nor on any satellites. The projected distance between 2M1207 b and its primary is at least 55 AU, and possibly more, giving it an orbital period of no less than 2450 years. It is possible that the planet is in fact a line-of-sight optical binary with the brown dwarf, and is not actually in orbit around 2M1207 at all. Currently the possibility is considered remote. See alsoReferences
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