T. Sivarani et al 2009 ApJ 694 L140 doi:10.1088/0004-637X/694/2/L140
SDSS J125637-022452: A HIGH PROPER MOTION L SUBDWARF
FREE ISSUET. Sivarani1,2, S. Lépine3, A. K. Kembhavi2 and J. Gupchup2,4
Show affiliationsWe 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.
- Keywords
Galaxy: halo; stars: individual (SDSS J125637-022452); stars: low-mass, brown dwarfs; subdwarfs
- PACS
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97.20.Vs Low luminosity stars, subdwarfs, and brown dwarfs
95.80.+p Astronomical catalogs, atlases, sky surveys, databases, retrieval systems, archives, etc.
97.10.Wn Proper motions and radial velocities (line-of-sight velocities); space motions
97.20.Tr Population II stars (horizontal branch, metal poor, etc.)
98.62.Lv Stellar content and populations; radii; morphology and overall structure
- Subjects
- Dates
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Issue 2 (2009 April 1)
Received 2008 December 26, accepted for publication 2009 January 21
Published 2009 March 13
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SDSS J125637-022452: A High Proper Motion L Subdwarf
T. Sivarani et al 2009 ApJ 694 L140
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