Astronomy:2M1207

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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.[1][2]

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,[3] 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.[5] 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; fr] reported a more accurate distance (53 ± 6 parsecs) to 2M1207 using the moving cluster method.[6] 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.[7][8] 2M1207 was first suspected to have such a disk because of its broad Hα line. This was later confirmed by ultraviolet spectroscopy.[8] The existence of a dust disk has also been confirmed by infrared observations[9] and with ALMA.[10] In general, accretion from disks are 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] While previous observations with the Spitzer spectrograph already detected acetylene (C2H2) emission in the disk of 2M1207, new observations with MIRI revealed emission of a wide variety of chemicals in the disk, showing a carbon-rich chemistry. In this study 2M1207 and ISO-ChaI 147 showed the largest number of organic molecules, including the only detection of ethylene (C2H4) in this sample. The detected chemicals include 9 hydrocarbons, with diacetylene (C4H2) and benzene (C6H6) being two prominent emission lines in the spectrum of 2M1207. Other emissions by chemicals in the disk are hydrogen gas (H2), hydrogen cyanide (HCN) and carbon dioxide (CO2).[14]

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.[15]

The 2M1207A planetary system[5][10][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 5.5±0.5[5] MJ ≥ 49.8 ± 1.1[lower-alpha 1] 633–20046 0.02–0.98 13–150° 1.399 +0.008−0.010[17] RJ

See also

Notes

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References

  1. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named mohanty
  2. ↑ 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. doi:10.1051/0004-6361:200400056. Bibcode: 2004A&A...425L..29C. 
  3. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named sb
  4. ↑ 4.0 4.1 4.2 "The Distance to the 2M1207 System" , Eric Mamajek, November 8, 2007. Accessed on line June 15, 2008.
  5. ↑ 5.0 5.1 5.2 Luhman, K. L.; Tremblin, P.; Birkmann, S. M.; Manjavacas, E.; Valenti, J.; Alves de Oliveira, C.; Beck, T. L.; Giardino, G. et al. (2023-06-01). "JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B". The Astrophysical Journal 949 (2): L36. doi:10.3847/2041-8213/acd635. ISSN 0004-637X. Bibcode: 2023ApJ...949L..36L. 
  6. ↑ Mamajek (2005). "A Moving Cluster Distance to the Exoplanet 2M1207b in the TW Hydrae Association". The Astrophysical Journal 634 (2): 1385–1394. doi:10.1086/468181. Bibcode: 2005ApJ...634.1385M. 
  7. ↑ More Sun-like stars may have planetary systems than currently thought , library, Origins program, NASA. Accessed on line June 16, 2008.
  8. ↑ 8.0 8.1 Gizis, John E.; Shipman, Harry L.; Harvin, James A. (2005). "First Ultraviolet Spectrum of a Brown Dwarf: Evidence for H 2 Fluorescence and Accretion". The Astrophysical Journal 630 (1): L89–L91. doi:10.1086/462414. Bibcode: 2005ApJ...630L..89G. 
  9. ↑ Riaz, Basmah; Gizis, John E.; Hmiel, Abraham (2006). "Spitzer Observations of Two TW Hydrae Association Brown Dwarfs". The Astrophysical Journal 639 (2): L79–L82. doi:10.1086/502647. Bibcode: 2006ApJ...639L..79R. 
  10. ↑ 10.0 10.1 Ricci, L.; Cazzoletti, P.; Czekala, I.; Andrews, S. M.; Wilner, D.; Szűcs, L.; Lodato, G.; Testi, L. et al. (2017-07-01). "ALMA Observations of the Young Substellar Binary System 2M1207". The Astronomical Journal 154 (1): 24. doi:10.3847/1538-3881/aa78a0. ISSN 0004-6256. Bibcode: 2017AJ....154...24R. 
  11. ↑ 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.
  12. ↑ Whelan 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. doi:10.1086/516734. Bibcode: 2007ApJ...659L..45W. 
  13. ↑ Small Stars Create Big Fuss, Ker Than, May 28, 2007, space.com. Accessed on line June 15, 2008.
  14. ↑ Arabhavi, A. M.; Kamp, I.; Henning, Th.; van Dishoeck, E. F.; Jang, H.; Waters, L. B. F. M.; Christiaens, V.; Gasman, D. et al. (2025). "MINDS: The very low-mass star and brown dwarf sample. Detections and trends in the inner disk gas". Astronomy & Astrophysics 699: A194. doi:10.1051/0004-6361/202554109. Bibcode: 2025A&A...699A.194A. 
  15. ↑ Elena, Manjavacas; Tremblin, Pascal; Birkmann, Stephan; Valenti, Jeff; Alves de Oliveira, Catarina; Beck, Tracy L.; Giardino, G.; Luetzgendorf, N. et al. (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. https://ui.adsabs.harvard.edu/abs/2024arXiv240204230M/abstract. 
  16. ↑ Blunt, Sarah; Nielsen, Eric L.; De Rosa, Robert J.; Konopacky, Quinn M.; Ryan, Dominic; Wang, Jason J.; Pueyo, Laurent; Rameau, Julien et al. (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. doi:10.3847/1538-3881/aa6930. ISSN 0004-6256. Bibcode: 2017AJ....153..229B. 
  17. ↑ Zhang, Zhoujian; Mollière, Paul; Fortney, Jonathan J.; Marley, Mark S. (August 2025). "Elemental Abundances of Planets and Brown Dwarfs Imaged around Stars (ELPIS). II. The Jupiter-like Inhomogeneous Atmosphere of the First Directly Imaged Planetary-mass Companion 2MASS 1207 b". ADS (The Astronomical Journal) 170 (2). doi:10.48550/arXiv.2502.18559. https://ui.adsabs.harvard.edu/abs/2025AJ....170...64Z/abstract. Retrieved 27 October 2025. 

Coordinates: Sky map 12h 07m 33.47s, −39° 32′ 54.0″




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