Microscopic diffusion and subdwarfs
Astrophysics
2007-05-23 v1
Abstract
The recent distance determinations by HIPPARCOS have allowed to locate very precisely a reasonable set of subdwarfs in the HR diagram. A detailed comparison with evolutionary models is now possible and it has been recently claimed that the observed lower part of the main-sequence is cooler than the computed one. In this paper we show that microscopic diffusion could be the physical explanation of such a systematic shift. We emphazise the fact that, as diffusion alters surface abundances, the initial metal content of the stellar material is higher than the present one. A "calibration" procedure is necessary when comparing observed and theoretical HR diagram, to take into account this effect.
Keywords
Cite
@article{arxiv.astro-ph/9902160,
title = {Microscopic diffusion and subdwarfs},
author = {P. Morel and A. Baglin},
journal= {arXiv preprint arXiv:astro-ph/9902160},
year = {2007}
}
Comments
latex A&A, 8 pages, 8 figures, accepted by A&A