Английская Википедия:2MASS J09373487+2931409

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2MASS J09373487+2931409, or 2MASSI J0937347+293142 (abbreviated to 2MASS 0937+2931) is a brown dwarf of spectral class T6,Шаблон:R located in the constellation Leo about 19.96 light-years from Earth.Шаблон:R

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).Шаблон:R

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.Шаблон:R A less precise parallax of this object, measured under U.S. Naval Observatory Infrared Astrometry Program, was published in 2004 by Vrba et al.Шаблон:R

Properties

2MASS 0937+2931 has an unusual spectrum, indicating a metal-poor atmosphere and/or a high surface gravity (high pressure at the surface).Шаблон:R 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.Шаблон:R No optical variability was detected as in 2014.

See also

The other 10 brown dwarfs, presented in Burgasser et al. (2002):

• 2MASS 0243-2453 (T6)
• 2MASS 0415-0935 (T8)
• 2MASS 0727+1710 (T7)
• List of stars in Leo

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)