Sivarani, T. ; Lepine, S. ; Kembhavi, A. K. ; Gupchup, J. (2009) SDSS J125637-022452: a high proper motion L subdwarf Astrophysical Journal Letters, 694 (2). L140-L143. ISSN 0004-637X
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Official URL: http://iopscience.iop.org/1538-4357/694/2/L140
Related URL: http://dx.doi.org/10.1088/0004-637X/694/2/L140
Abstract
We report the discovery of a high proper motion L subdwarf (μ = 0.617" yr-1) in the Sloan Digital Sky Survey (SDSS) spectral database. The optical spectrum from the star SDSS J125637-022452 has mixed spectral features of both late-M spectral subtype (strong TiO and CaH at 7000 Å) and mid-L spectral subtype (strong wings of KI at 7700 Å, CrH, and FeH), which is interpreted as the signature of a very low-mass, metal-poor star (ultracool subdwarf) of spectral-type sdL. The near-infrared (NIR) (J - Ks) colors from 2MASS show the object to be significantly bluer compared to normal L dwarfs, which is probably due to a strong collision-induced absorption (CIA) from the H2 molecule. This is consistent with the idea that CIA from H2 is more pronounced at low metallicities. Proper motion and radial velocity measurements also indicate that the star is kinematically "hot" and probably associated with the Galactic halo population.
Item Type: | Article |
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Source: | Copyright of this article belongs to American Astronomical Society. |
Keywords: | Galaxy: Halo; Stars: Individual (SDSS J125637-022452); Stars: Low-mass; Brown Dwarfs; Subdwarfs |
ID Code: | 25470 |
Deposited On: | 06 Dec 2010 13:21 |
Last Modified: | 17 May 2016 08:56 |
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