2M1207
12h 07m 33.47s, −39° 32′ 54.0″ European Southern Observatory infrared image of 2M1207 (bluish) and companion planet 2M1207b (reddish), taken in 2004. | |
| Observation data ICRS )
| |
|---|---|
| Constellation | Centaurus |
| Right ascension | 12h 07m 33.47s[1] |
| Declination | −39° 32′ 54.0″[1] |
| Apparent magnitude (V) | 20.15[2] |
| Characteristics | |
| Spectral type | M8IVe C[1] |
| V−R color index | +2.1[2] |
| R−I color index | +2.1[2] |
| Details | |
| Mass | ~0.025[4] M☉ |
| Radius | ~0.25[5] R☉ |
| Luminosity | ~0.002[5] L☉ |
| Temperature | 2550 ± 150[5] K |
| Age | 5·106 to 10·106[5] years |
| Other designations | |
2MASSW J1207334−393254, 2MASS J12073346-3932539, TWA 27[1] | |
| Database references | |
| SIMBAD | data |
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.[5][6]
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,[1] it is very young, and probably a member of the TW Hydrae association. Its estimated mass is around 25 Jupiter masses.[4] The companion, 2M1207b, is estimated to have a mass of 5–6 Jupiter masses.[7] 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.
Planetary system
Like classical
2M1207b shows weak accretion from a disk, inferred from emission lines of hydrogen and helium in medium-resolution NIRSpec data. Surprisingly 2M1207b does not show absorption due to methane, which was predicted to be present for this object. It was suggested that very young objects have a L/T-transition starts at a later spectral type.[16]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| circumstellar disk | 9.4±1.5 AU | 35+20 −15° |
— | |||
| b | 5–6 MJ | ≥49.8 ± 1.1[18] | 633-20046 | 0.02-0.98 | 13-150° | — |
See also
- Lists of exoplanets
- Direct imaging of extrasolar planets
References
- ^ a b c d e "TWA 27". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved June 15, 2008.
- ^ .
- ^ .
- ^ a b c d "The Distance to the 2M1207 System" Archived 2008-01-24 at the Wayback Machine, Eric Mamajek, November 8, 2007. Accessed on line June 15, 2008.
- ^ doi:10.1086/510877.
- S2CID 15948759.
- ^ ISSN 0004-637X.
- S2CID 17162407.
- ^ More Sun-like stars may have planetary systems than currently thought Archived 2008-09-17 at the Wayback Machine, library, Origins program, NASA. Accessed on line June 16, 2008.
- ^ doi:10.1086/462414.
- doi:10.1086/502647.
- ^ ISSN 0004-6256.
- ISBN 3-540-20171-8.
- S2CID 14575014.
- ^ Small Stars Create Big Fuss, Ker Than, May 28, 2007, space.com. Accessed on line June 15, 2008.
- arXiv:2402.04230.
- ISSN 0004-6256.
- ^ From Gaia distance of 64.7 ± 0.5 parsec and observed angular separation of 769 ± 10 milliarseconds (angular separation from Mohanty 2007, above.) Real semimajor axis might be higher due to viewing angle and eccentricity of the orbit.
External links
- Space.com - Astronomers Confident: Planet Beyond Solar System Has Been Photographed
- Space.com article on the discovery
- Jean Schneider (2011). "Notes for star 2M1207". Extrasolar Planets Encyclopaedia. Archived from the original on 6 October 2011. Retrieved 3 October 2011.
- "A Giant Planet Candidate Near a Young Brown Dwarf" (PDF) from the European Southern Observatory.
- "A Moving Cluster Distance to the Exoplanet 2M1207b in the TW Hydrae Association"
