2MASS J06164006-6407194: The First Outer Halo L Subdwarf
Abstract
We present the serendipitous discovery of an L subdwarf, 2MASS J06164006-6407194, in a search of the Two Micron All Sky Survey for T dwarfs. Its spectrum exhibits features indicative of both a cool and metal poor atmosphere including a heavily pressured-broadened K I resonant doublet, Cs I and Rb I lines, molecular bands of CaH, TiO, CrH, FeH, and H2O, and enhanced collision induced absorption of H2. We assign 2MASS 0616-6407 a spectral type of sdL5 based on a comparison of its red optical spectrum to that of near solar-metallicity L dwarfs. Its high proper motion (mu =1.405+-0.008 arcsec yr-1), large radial velocity (Vrad = 454+-15 km s-1), estimated uvw velocities (94, -573, 125) km s-1 and Galactic orbit with an apogalacticon at ~29 kpc are indicative of membership in the outer halo making 2MASS 0616-6407 the first ultracool member of this population.
Cite
@article{arxiv.0902.1059,
title = {2MASS J06164006-6407194: The First Outer Halo L Subdwarf},
author = {M. C. Cushing and D. Looper and A. J. Burgasser and J. D. Kirkpatrick and J. Faherty and K. Cruz and A. Sweet and R. E. Sanderson},
journal= {arXiv preprint arXiv:0902.1059},
year = {2014}
}
Comments
Accepted for publication in ApJ