2MASSI J0937347+293142
Coordinates: 
09h 37m 34.9s, +29° 31′ 41″
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Leo |
| Right ascension | 09h 37m 34.9s |
| Declination | 29° 31′ 41″ |
| Characteristics | |
| Spectral type | T6p |
| Astrometry | |
| Proper motion (μ) | RA: 944.15 ± 1.24 mas/yr Dec.: −1319.78 ± 1.21 mas/yr |
| Parallax (π) | 163.39 ± 1.76[1] mas |
| Distance | 20.0 ± 0.2 ly (6.12 ± 0.07 pc) |
| Details | |
| Mass | 0.03[2] M☉ |
| Temperature | 780 - 840 K |
| Other designations | |
2MASS J09373487+2931409 2MASSI J0937347+293142 2MASS 0937+2931 | |
| Database references | |
| SIMBAD | data |
2MASS J09373487+2931409, or 2MASSI J0937347+293142 (abbreviated to 2MASS 0937+2931) is a brown dwarf of spectral class T6,[3][4] located in the constellation Leo about 19.96 light-years from Earth.[1].
Discovery
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 observations 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).[3]
Distance
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.[1] A less precise parallax of this object, measured under U.S. Naval Observatory Infrared Astrometry Program, was published in 2004 by Vrba et al.[5]
2MASSI J0937347+293142 distance estimates
| Source | Parallax, mas | Distance, pc | Distance, ly | Distance, Pm | Ref. |
|---|---|---|---|---|---|
| Vrba et al. (2004) | 162.84±3.88 | 6.14+0.15 −0.14 |
20±0.5 | 189.5+4.6 −4.4 |
[5] |
| Schilbach et al. (2009) | 163.39±1.76 | 6.12±0.07 | 19.96+0.22 −0.21 |
188.9+2.1 −2 |
[1] |
| RECONS TOP100 (2012) | 163.30±1.60[nb 1] | 6.12±0.06 | 19.97+0.2 −0.19 |
189+1.9 −1.8 |
[6] |
Non-trigonometric distance estimates are marked in italic. The most precise estimate is marked in bold.
Properties
2MASS 0937+2931 has an unusual spectrum, indicating a metal-poor atmosphere and/or a high surface gravity (high pressure at the surface).[3] 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.[2]
See also
The other 10 brown dwarfs, presented in Burgasser et al. (2002):[3]
- 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)
References
- ↑ 1.0 1.1 1.2 1.3 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.
- ↑ 2.0 2.1 Research Consortium on Nearby Stars, Georgia State University (January 1, 2012). "The 100 nearest star systems". RECONS. Retrieved 2012-06-11.
- ↑ 3.0 3.1 3.2 3.3 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.
- ↑ 5.0 5.1 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.
- ↑ "RECONS TOP100". THE ONE HUNDRED NEAREST STAR SYSTEMS brought to you by RECONS (Research Consortium On Nearby Stars). 2012.
Notes
- ↑ Weighted parallax, based on parallaxes from Vrba et al. (2004) and Schilbach et al. (2009).
External links
- 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)
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