2M1207
![]() 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[1] |
Declination | −39° 32′ 54.0″[1] |
Apparent magnitude (V) | 20.15[2] |
Characteristics | |
Spectral type | M8[1] |
V−R color index | 2.1[2] |
R−I color index | 2.1[2] |
Astrometry | |
Parallax (π) | 19.1 ± 0.4 mas[2] |
Distance | 172 ± 3 ly (52.75 ± 1.0[3] pc) |
Details | |
Mass | ~0.025[3] M☉ |
Radius | ~0.25[4] R☉ |
Luminosity | ~0.002[4] L☉ |
Temperature | 2550 ± 150[4] K |
Age | 5·106 to 10·106[4] years |
Other designations | |
2MASSW J1207334−393254[1] | |
Database references | |
SIMBAD | data |
2M1207, 2M1207A or 2MASSW J1207334−393254 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.[4][5]
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.[3] The companion, 2M1207b, is estimated to have a mass of 3–10 Jupiter masses.[6] 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.[3] In December 2005, American astronomer Eric Mamajek reported a more accurate distance (53 ± 6 parsecs) to 2M1207 using the moving cluster method.[7] 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.[3]
Like classical T Tauri stars, many brown dwarfs are surrounded by disks of gas and dust which accrete onto the brown dwarf.[8][9] 2M1207 was first suspected to have such a disk because of its broad Hα line. This was later confirmed by ultraviolet spectroscopy.[9] The existence of a dust disk has also been confirmed by infrared observations.[10] In general, accretion from disks is known to produce fast-moving jets, perpendicular to the disk, of ejected material.[11] This has also been observed for 2M1207; an April 2007 paper in the Astrophysical Journal reports that this brown dwarf is spouting jets of material from its poles.[12] The jets, which extend around 109 kilometers into space, were discovered using the Very Large Telescope (VLT) at the European Southern Observatory. Material in the jets streams into space at a few kilometers per second.[13]
Companion | Mass | Observed separation (AU) |
b | 3–10[6] MJ | 40.6 ± 1.3[14] |
References
- ^ a b c d e NAME 2M1207A, entry, SIMBAD. Accessed on line June 15, 2008.
- ^ a b c d An accurate distance to 2M1207Ab, C. Ducourant, R. Teixeira, G. Chauvin, G. Daigne, J.-F. Le Campion, Inseok Song, and B. Zuckerman, Astronomy and Astrophysics 477, #1 (January 2008), pp. L1–L4. Bibcode:2008A&A...477L...1D doi:10.1051/0004-6361:20078886.
- ^ a b c d e "The Distance to the 2M1207 System", Eric Mamajek, November 8, 2007. Accessed on line June 15, 2008.
- ^ a b c d e The Planetary Mass Companion 2MASS 1207-3932B: Temperature, Mass, and Evidence for an Edge-on Disk, Subhanjoy Mohanty, Ray Jayawardhana, Nuria Huelamo, and Eric Mamajek, Astrophysical Journal 657, #2 (March 2007), pp. 1064–1091. Bibcode:2007ApJ...657.1064M doi:10.1086/510877.
- ^ Chauvin, G. (2004). "A Giant Planet Candidate near a Young Brown Dwarf". Astron. Astrophys. 425: L29–L32. Retrieved 2008-11-16.
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suggested) (help) - ^ a b Star: 2M1207, Extrasolar Planets Encyclopaedia. Accessed on line June 15, 2008.
- ^ Mamajek (2005). "A Moving Cluster Distance to the Exoplanet 2M1207b in the TW Hydrae Association". The Astrophysical Journal. 634: 1385–1394. doi:10.1086/468181.
- ^ More Sun-like stars may have planetary systems than currently thought, library, Origins program, NASA. Accessed on line June 16, 2008.
- ^ a b First Ultraviolet Spectrum of a Brown Dwarf: Evidence for H2 Fluorescence and Accretion, John E. Gizis, Harry L. Shipman, and James A. Harvin, Astrophysical Journal 630, #1 (September 2005), pp. L89–L91. Bibcode:2005ApJ...630L..89G doi:10.1086/462414.
- ^ Spitzer Observations of Two TW Hydrae Association Brown Dwarfs, Basmah Riaz, John E. Gizis, and Abraham Hmiel, Astrophysical Journal 639, #2 (March 2006), pp. L79–L82. Bibcode:2006ApJ...639L..79R doi:10.1086/502647.
- ^ Accretion-ejection models of astrophysical jets, R. E. Pudritz, in Accretion Disks, Jets and High-energy Phenomena in Astrophysics, Vassily Beskin, Gilles Henri, Francois Menard, Guy Pelletier, and Jean Dalibard, eds., NATO Advanced Study Institute, Les Houches, session LXXVIII, EDP Sciences/Springer, 2003. ISBN 3540201718.
- ^ Whelan; et al. (April 10, 2007). "Discovery of a Bipolar Outflow from 2MASSW J1207334-393254, a 24 MJup Brown Dwarf". The Astrophysical Journal. 659: L45–L48. Bibcode:2007ApJ...659L..45W. doi:10.1086/516734.
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(help) - ^ Small Stars Create Big Fuss, Ker Than, May 28, 2007, space.com. Accessed on line June 15, 2008.
- ^ From estimated distance of 52.75 ± 1.0 parsec and observed angular separation of 769 ± 10 milliarseconds (angular separation from Mohanty 2007, above.)
External links
- Space.com - Astronomers Confident: Planet Beyond Solar System Has Been Photographed
- Space.com article on the discovery
- Extrasolar Planets Encyclopedia page on 2M1207
- "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"
- "The Distance to the 2M1207 System"