Epoch J2000 Equinox J2000
|Right ascension||09h 37m 34.9s|
|Declination||29° 31′ 41″|
|Proper motion (μ)||RA: 944.15 ± 1.24 mas/yr
Dec.: −1319.78 ± 1.21 mas/yr
|Parallax (π)||163.39 ± 1.76 mas|
|Distance||20.0 ± 0.2 ly
(6.12 ± 0.07 pc)
|Temperature||780 - 840 K|
2MASS J09373487+2931409, or 2MASSI J0937347+293142 (abbreviated to 2MASS 0937+2931) is a brown dwarf of spectral class T6, located in the constellation Leo about 19.96 light-years from Earth..
2MASS 0937+2931 was discovered in 2002 by Adam J. Burgasser et al. from Two Micron All-Sky Survey (2MASS), conducted from 1997 to 2001. Follow-up obsrvations were made in 1998—2001 using the Near-Infrared Camera, mounted on the Palomar 60 inch (1.5 m) Telescope; CTIO Infrared Imager (CIRIM) and Ohio State Infrared Imager/Spectrometer (OSIRIS), mounted on the Cerro Tololo Inter-American Observatory (CTIO) 1.5 m Telescope; and some additional observations were made using the Near Infrared Camera (NIRC), mounted on the Keck I 10 m telescope, and nearinfrared camera D78, mounted on the Palomar 5 m Hale Telescope. In 2002 Burgasser et al. published a paper, where they defined new spectral subtypes T1—T8, and presented discovery of 11 new T-type brown dwarfs, among which also was 2MASS 0937+2931. This 11 objects were among the earliest T-type brown dwarfs ever discovered: before this, the total number of known T-type objects was 13, and this discoveries increased it up to 24 (apart from additional T-type dwarfs, identified by Geballe et al. 2001 in SDSS data).
Currently the most precise distance estimate of 2MASS 0937+2931 is trigonometric parallax, published in 2009 by Schilbach et al.: 163.39 ± 1.76 mas, corresponding to a distance 6.12 ± 0.07 pc, or 19.96 ± 0.22 ly. A less precise parallax of this object, measured under U.S. Naval Observatory Infrared Astrometry Program, was published in 2004 by Vrba et al.
2MASS 0937+2931 distance estimates
|Source||Parallax, mas||Distance, pc||Distance, ly||Ref.|
|Vrba et al. (2004)||162.84 ± 3.88||6.14 ± 0.15||20.0 ± 0.5|||
|Schilbach et al. (2009)||163.39 ± 1.76||6.12 ± 0.07||19.96 ± 0.22|||
Non-trigonometric distance estimates are marked in italic. The best estimate is marked in bold.
2MASS 0937+2931 has an unusual spectrum, indicating a metal-poor atmosphere and/or a high surface gravity (high pressure at the surface). Its effective temperature is estimated at about 800 Kelvin. The Research Consortium On Nearby Stars (RECONS) estimates the brown dwarf to be 0.03 solar masses.
The other 10 brown dwarfs, presented in Burgasser et al. (2002):
- 2MASS 0243-2453 (T6)
- 2MASS 0415-0935 (T8)
- 2MASS 0727+1710 (T7)
- 2MASS 0755+2212 (T5)
- 2MASS 1534-2952 (T5.5)
- 2MASS 1546-3325 (T5.5)
- 2MASS 1553+1532 (T7)
- 2MASS 2254+3123 (T5)
- 2MASS 2339+1352 (T5.5)
- 2MASS 2356-1553 (T6)
- Schilbach, E.; Röser, S.; Scholz, R.-D. (2009). "Trigonometric parallaxes of ten ultracool subdwarfs". Astronomy and Astrophysics 493 (2): L27–L30. arXiv:0811.4136. Bibcode:2009A&A...493L..27S. doi:10.1051/0004-6361:200811281.
- Research Consortium on Nearby Stars, Georgia State University (January 1, 2012). "The 100 nearest star systems". RECONS. Retrieved 2012-06-11.
- Burgasser, A. J.; Kirkpatrick, J. D.; Brown, M. E.; Reid, I. N.; Burrows, A.; Liebert, J.; Matthews, K.; Gizis, J. E.; Dahn, C. C.; Monet, D. G.; Cutri, R. M.; Skrutskie, M. F. (2002). "The Spectra of T Dwarfs. I. Near-Infrared Data and Spectral Classification". The Astrophysical Journal 564 (1): 421–451. arXiv:astro-ph/0108452. Bibcode:2002ApJ...564..421B. doi:10.1086/324033.
- "2MASS J09373487+2931409 -- Brown Dwarf (M<0.08solMass)". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2012-11-26.
- Vrba, F. J.; Henden, A. A.; Luginbuhl, C. B.; Guetter, H. H.; Munn, J. A.; Canzian, B.; Burgasser, A. J.; Kirkpatrick, J. Davy; Fan, X.; Geballe, T. R.; Golimowski, D. A.; Knapp, G. R.; Leggett, S. K.; Schneider, D. P.; Brinkmann, J. (2004). "Preliminary Parallaxes of 40 L and T Dwarfs from the US Naval Observatory Infrared Astrometry Program". The Astronomical Journal 127 (5): 2948–2968. arXiv:astro-ph/0402272. Bibcode:2004AJ....127.2948V. doi:10.1086/383554.
- Burgasser et al.: „A Method for Determining the Physical Properties of the Coldest Known Brown Dwarfs“; in: The Astrophysical Journal, Vol. 639, Issue 2, S. 1095ff. (2006)
- Cushing et al.: „A Spitzer Infrared Spectrograph Spectral Sequence of M, L, and T Dwarfs“; in: The Astrophysical Journal, Vol. 648, Issue 1, S. 614ff. (2006)