2M1207

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2M1207
Observation data
Epoch J2000.0
Constellation
(pronunciation)		 Centaurus
Right ascension 12h 07m 33.4s
Declination −39° 32′ 54″
Apparent magnitude (V) 20.15
Distance 172 ly
(53 pc)
Spectral type M8
Other designations
2MASSW J1207334−393254
European Southern Observatory infrared image of 2M1207 (bluish) and companion planet 2M1207b (reddish), taken in 2004.
European Southern Observatory infrared image of 2M1207 (bluish) and companion planet 2M1207b (reddish), taken in 2004.

2M1207, 2M1207A or 2MASSW J1207334−393254 is a brown dwarf located in the constellation Centaurus; a companion object, 2M1207b, is believed to be one of the first extrasolar planets to be directly imaged, and is the first exoplanet to be discovered in orbit of a brown dwarf.

2M1207 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 53 parsecs away; 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 around 21 Jupiter masses and 1.8 times the radius of Jupiter. The planet is estimated to be 5 Jupiter Masses and is still glowing red hot and will shrink to Jupiter's current size as it cools over the next few billion years.

In December 2005, American astronomer Eric Mamajek reported a more accurate distance (53+-6 parsecs) to 2M1207 using the moving cluster method[1]. The new distance (revised downwards from 70 parsecs) results in a fainter luminosity for 2M1207A, and its mass was revised downwards from an original value of 25 Jupiter masses. Recent trigonometric parallax results have confirmed the moving cluster distance, leading to a distance estimate of 53+-1 parsec or 172+-3 light years.

A report in the March '07 issue of the Astrophysical Journal reports that this brown dwarf is spouting jets of material from its poles. [2]

2M1207's streaming jets were discovered using the European Southern Observatory's Very Large Telescope (VLT). The jets extend about 620 million miles (1 billion km) into space and are speeding away from the brown dwarf at a few kilometers per second.

"Preliminary results suggest that a brown-dwarf jet is just scaled down from what we see in a low mass star," said study leader Emma Whelan of the Dublin Institute for Advanced Physics in Ireland.


[edit] References

  1. ^ Mamajek (2005). "A Moving Cluster Distance to the Exoplanet 2M1207b in the TW Hydrae Association". The Astrophysical Journal 634: 1385 - 1394. 
  2. ^ Whelan et al. (2007). "Discovery of a Bipolar Outflow from 2MASSW J1207334-393254, a 24 MJup Brown Dwarf". The Astrophysical Journal 659: L45 – L48. doi:10.1086/516734.