Astronomy:2M1207

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Short description: Brown dwarf in the constellation Centaurus
2M1207
2M1207b - First image of an exoplanet.jpg
European Southern Observatory infrared image of 2M1207 (bluish) and companion planet 2M1207b (reddish), taken in 2004.
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
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]
Astrometry
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[3] mas
Distance211 ± 2 ly
(64.7 ± 0.5 pc)
Details
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
SIMBADdata

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]

The 2M1207A planetary system[7][12][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[17] 633-20046 0.02-0.98 13-150° —

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 "TWA 27". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=TWA+27. 
  2. ↑ 2.0 2.1 2.2 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. ↑ 3.0 3.1 3.2 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  4. ↑ 4.0 4.1 4.2 4.3 "The Distance to the 2M1207 System" , Eric Mamajek, November 8, 2007. Accessed on line June 15, 2008.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 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. doi:10.1051/0004-6361:200400056. Bibcode: 2004A&A...425L..29C. 
  7. ↑ 7.0 7.1 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: L36. doi:10.3847/2041-8213/acd635. ISSN 0004-637X. https://ui.adsabs.harvard.edu/abs/2023ApJ...949L..36L. 
  8. ↑ 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. 
  9. ↑ More Sun-like stars may have planetary systems than currently thought , library, Origins program, NASA. Accessed on line June 16, 2008.
  10. ↑ 10.0 10.1 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. ↑ 12.0 12.1 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: 24. doi:10.3847/1538-3881/aa78a0. ISSN 0004-6256. https://ui.adsabs.harvard.edu/abs/2017AJ....154...24R. 
  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 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. 
  15. ↑ Small Stars Create Big Fuss, Ker Than, May 28, 2007, space.com. Accessed on line June 15, 2008.
  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: 229. doi:10.3847/1538-3881/aa6930. ISSN 0004-6256. https://ui.adsabs.harvard.edu/abs/2017AJ....153..229B. 
  17. ↑ 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

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



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