2M1207
2M1207, 2M1207A or 2MASS J12073346–3932539 is a brown dwarf located in the constellation Centaurus; a companion object, 2M1207b, may be the first extrasolar planetary-mass companion to be directly imaged, and is the first discovered orbiting a brown dwarf.
European Southern Observatory infrared image of 2M1207 (bluish) and companion planet 2M1207b (reddish), taken in 2004. | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 12h 07m 33.47s |
| Declination | −39° 32′ 54.0″ |
| Apparent magnitude (V) | 20.15 |
| Characteristics | |
| Spectral type | M8IVe C |
| V−R color index | +2.1 |
| R−I color index | +2.1 |
| Astrometry | |
| Proper motion (μ) | RA: −64.040±0.087 mas/yr Dec.: −23.678±0.072 mas/yr |
| Parallax (π) | 15.4624 ± 0.1163 mas |
| Distance | 211 ± 2 ly (64.7 ± 0.5 pc) |
| Details | |
| Mass | ~0.025 M☉ |
| Radius | ~0.25 R☉ |
| Luminosity | ~0.002 L☉ |
| Temperature | 2550 ± 150 K |
| Age | 5·106 to 10·106 years |
| Other designations | |
2MASSW J1207334−393254, 2MASS J12073346-3932539, TWA 27 | |
| Database references | |
| SIMBAD | data |
2M1207 was discovered during the course of the 2MASS infrared sky survey: hence the "2M" in its name, followed by its celestial coordinates. With a fairly early (for a brown dwarf) spectral type of M8, it is very young, and probably a member of the TW Hydrae association. Its estimated mass is around 25 Jupiter masses. The companion, 2M1207b, is estimated to have a mass of 5–6 Jupiter masses. Still glowing red hot, it will shrink to a size slightly smaller than Jupiter as it cools over the next few billion years.
An initial photometric estimate for the distance to 2M1207 was 70 parsecs. In December 2005, American astronomer Eric Mamajek reported a more accurate distance (53 ± 6 parsecs) to 2M1207 using the moving cluster method. The new distance gives a fainter luminosity for 2M1207. Recent trigonometric parallax results have confirmed this moving cluster distance, leading to a distance estimate of 53 ± 1 parsec or 172 ± 3 light years.