Kinematics of nearby subdwarfs
Abstract
A sample of subdwarfs with accurate space velocities and standarized metallicities is presented. This was constructed by combining Hipparcos parallaxes ond proper motions with radial velocities and metallicities from Carney et al. (1994; CLLA). The accurate Hipparcos parallaxes lead to an - upward - correction factor of 11% of the photometric distance scale of CLLA. The kinematical behaviour of the subdwarfs is discussed in particular in relation to their metallicities. Most of the stars turn out to be thick disk stars, but the sample contains also many genuine halo stars. While the extreme metal poor halo does not rotate, a population of subdwarfs with metallicities in the range -1.6 < [Fe/H] < -1.0 dex appears to rotate around the galactic center with a mean rotation speed of about 100 km/s.
Keywords
Cite
@article{arxiv.astro-ph/9811442,
title = {Kinematics of nearby subdwarfs},
author = {B. Fuchs and H. Jahreiss and R. Wielen},
journal= {arXiv preprint arXiv:astro-ph/9811442},
year = {2009}
}
Comments
Latex, 4 pages, 6 figures. To appear in the proceedings of the `Galaxy Evolution' conference held in Meudon, September, 21 - 25, 1998