Grids of pre-main sequence stellar models. The accretion scenario at Z=0.001 and Z=0.020

Observatoire de Genève, CH-1290 Sauverny, Switzerland e-mail: paolo.bernasconi@obs.unige.ch

Received: 12 February 1996
Accepted: 5 April 1996

Abstract

I present and briefly discuss a new set of pre-main sequence (MS) evolutionary tracks computed in the framework of the accretion paradigm for star formation at metallicities Z=0.001 and Z=0.020. Improved birthlines are obtained from a time-dependent prescription for the accretion rate. These evolutionary sequences are better suited than the canonical approach which starts arbitrarily high on a luminous Hayashi adiabat, to interpret color-magnitude diagrams and ages of young stellar associations. They also constitute a (both physical and numerical) self-consistent extension to the post-MS stellar models previously published by the Geneva group (Schaller et al. 1992).