We report the identification of LP 400-22 (WD 2234+222) as a very low-mass and high-velocity white dwarf. The ultraviolet GALEX and optical photometric colors and a spectral line analysis of LP 400-22 show this star to have an effective temperature of 11080+/-140 K and a surface gravity of log g = 6.32+/-0.08. Therefore, this is a helium core white dwarf with a mass of 0.17 M_solar. The tangential velocity of this white dwarf is 414+/-43 km/s, making it one of the fastest moving white dwarfs known. We discuss probable evolutionary scenarios for this remarkable object.
@article{arxiv.astro-ph/0604470,
title = {LP 400-22, A very low-mass and high-velocity white dwarf},
author = {Adela Kawka and Stephane Vennes and Terry D. Oswalt and J. Allyn Smith and Nicole M. Silvestri},
journal= {arXiv preprint arXiv:astro-ph/0604470},
year = {2009}
}
Comments
accepted for publication in ApJ Letters, made minor corrections