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Coordinates: Sky map 12h 07m 33.47s, −39° 32′ 54.0″
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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]
Spectral type M8IVe[1]
V−R color index +2.1[2]
R−I color index +2.1[2]
Proper motion (μ) RA: −64.040±0.087[3] mas/yr
Dec.: −23.678±0.072[3] mas/yr
Parallax (π)15.4624 ± 0.1163 mas[3]
Distance211 ± 2 ly
(64.7 ± 0.5 pc)
Mass~0.025[4] M
Radius~0.25[5] R
Luminosity~0.002[5] L
Temperature2550 ± 150[5] K
Age5·106 to 10·106[5] years
Other designations
2MASSW J1207334−393254, 2MASS J12073346-3932539, TWA 27[1]
Database references

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.[4] In December 2005, American astronomer Eric Mamajek [fr] reported a more accurate distance (53 ± 6 parsecs) to 2M1207 using the moving cluster method.[8] 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.[4]

Planetary system


Like classical T Tauri stars, many brown dwarfs are surrounded by disks of gas and dust which accrete onto the brown dwarf.[9][10] 2M1207 was first suspected to have such a disk because of its broad Hα line. This was later confirmed by ultraviolet spectroscopy.[10] The existence of a dust disk has also been confirmed by infrared observations[11] and with ALMA.[12] In general, accretion from disks are known to produce fast-moving jets, perpendicular to the disk, of ejected material.[13] 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.[14] 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.[15]

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]

The 2M1207A planetary system[7][12][17]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
circumstellar disk 9.4±1.5 AU 35+20
b 5–6 MJ ≥49.8 ± 1.1[18] 633-20046 0.02-0.98 13-150°

See also



  1. ^ a b c d e "TWA 27". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved June 15, 2008.
  2. ^ a b c 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.
  3. ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  4. ^ 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.
  5. ^ 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.
  6. ^ Chauvin, G.; Lagrange, A.-M.; Dumas, C.; Zuckerman, B.; Mouillet, D.; Song, I.; Beuzit, J.-L.; Lowrance, P. (2004). "A Giant Planet Candidate near a Young Brown Dwarf". Astron. Astrophys. 425 (2): L29–L32. arXiv:astro-ph/0409323. Bibcode:2004A&A...425L..29C. doi:10.1051/0004-6361:200400056. S2CID 15948759.
  7. ^ a b Luhman, K. L.; Tremblin, P.; Birkmann, S. M.; Manjavacas, E.; Valenti, J.; Alves de Oliveira, C.; Beck, T. L.; Giardino, G.; Lützgendorf, N.; Rauscher, B. J.; Sirianni, M. (2023-06-01). "JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B". The Astrophysical Journal. 949 (2): L36. arXiv:2305.18603. Bibcode:2023ApJ...949L..36L. doi:10.3847/2041-8213/acd635. ISSN 0004-637X.
  8. ^ Mamajek (2005). "A Moving Cluster Distance to the Exoplanet 2M1207b in the TW Hydrae Association". The Astrophysical Journal. 634 (2): 1385–1394. arXiv:astro-ph/0507416. Bibcode:2005ApJ...634.1385M. doi:10.1086/468181. S2CID 17162407.
  9. ^ 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.
  10. ^ 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.
  11. ^ 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.
  12. ^ a b Ricci, L.; Cazzoletti, P.; Czekala, I.; Andrews, S. M.; Wilner, D.; Szűcs, L.; Lodato, G.; Testi, L.; Pascucci, I.; Mohanty, S.; Apai, D.; Carpenter, J. M.; Bowler, B. P. (2017-07-01). "ALMA Observations of the Young Substellar Binary System 2M1207". The Astronomical Journal. 154 (1): 24. arXiv:1706.03708. Bibcode:2017AJ....154...24R. doi:10.3847/1538-3881/aa78a0. hdl:10150/624920. ISSN 0004-6256.
  13. ^ 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 3-540-20171-8.
  14. ^ Whelan; Ray, T. P.; Randich, S.; Bacciotti, F.; Jayawardhana, R.; Testi, L.; Natta, A.; Mohanty, S.; et al. (April 10, 2007). "Discovery of a Bipolar Outflow from 2MASSW J1207334-393254, a 24 MJup Brown Dwarf". The Astrophysical Journal. 659 (1): L45–L48. arXiv:astro-ph/0703112. Bibcode:2007ApJ...659L..45W. doi:10.1086/516734. S2CID 14575014.
  15. ^ Small Stars Create Big Fuss, Ker Than, May 28, 2007, space.com. Accessed on line June 15, 2008.
  16. ^ Elena, Manjavacas; Tremblin, Pascal; Birkmann, Stephan; Valenti, Jeff; Alves de Oliveira, Catarina; Beck, Tracy L.; Giardino, G.; Luetzgendorf, N.; Rauscher, B. J.; Sirianni, M. (February 2024). "Medium Resolution 0.97-5.3 micron spectra of Very Young Benchmark Brown Dwarfs with NIRSpec onboard the James Webb Space Telescope". AJ. arXiv:2402.04230.
  17. ^ Blunt, Sarah; Nielsen, Eric L.; De Rosa, Robert J.; Konopacky, Quinn M.; Ryan, Dominic; Wang, Jason J.; Pueyo, Laurent; Rameau, Julien; Marois, Christian; Marchis, Franck; Macintosh, Bruce; Graham, James R.; Duchêne, Gaspard; Schneider, Adam C. (2017-05-01). "Orbits for the Impatient: A Bayesian Rejection-sampling Method for Quickly Fitting the Orbits of Long-period Exoplanets". The Astronomical Journal. 153 (5): 229. arXiv:1703.10653. Bibcode:2017AJ....153..229B. doi:10.3847/1538-3881/aa6930. ISSN 0004-6256.
  18. ^ 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.