EDP Sciences
Free access
Volume 367, Number 1, February III 2001
Page(s) 277 - 281
Section Formation, structure and evolution of stars
DOI http://dx.doi.org/10.1051/0004-6361:20000534

A&A 367, 277-281 (2001)
DOI: 10.1051/0004-6361:20000534

Research Note
Prediction for the first generation stars from a Galactic halo chemical evolution model with Miller-Scalo initial mass function

Y. Lu1, 2, G. Zhao1, L. C. Deng1, M. R. Cen2 and Y. C. Liang1

1  Beijing Astronomical Observatory, Datun Rd. 20A, Chaoyang, Beijing 100012, PR China
2  The Department of Physics, Normal University of Central China, Wuhan, Hubei 430079, PR China

(Received 11 August 2000 / Accepted 18 December 2000 )

A model of supernova-driven chemical evolution of the Galactic halo proposed by Tsujimoto et al. (1999) (TSY) is used to investigate the observations of the first generation stars (FGS). We assume in this paper that a star with a metallicity ${\rm [Fe/H]}\le -6$ is truly a FGS. We obtain FGS probabilities with the Miller-Scalo form of the stellar initial mass function and limit our model parameters to values consistent with the observed metallicity distributions of metal-poor stars in the range of $-4.0< {\rm [Fe/H]}< -1.0$. We find a metallicity distribution function (MDF) of the long-lived halo field stars for ${\rm [Fe/H]}< -1$ against the iron abundance in agreement with the observations. If the star formation in the halo is confined to individual gas clouds with masses from 1 107 to $1 10^8 M_\odot$, our model suggests that the probability of identifying FGS in the halo is about 6.14 10-5 to 6.14 10-6.

Key words: galaxy: evolution -- galaxy: halo-stars: abundance -- stars: formation -- supernovae: general

Offprint request: Y. Lu, ly@yac.bao.ac.cn

© ESO 2001