Formation of massive stars by growing accretion rate^*

Geneva Observatory, 1290 Sauverny, Switzerland e-mail: andre.maeder@obs.unige.ch

Corresponding author: R. Behrend, raoul.behrend@obs.unige.ch

Received: 3 April 2001
Accepted: 12 April 2001

Abstract

We perform calculations of pre-main sequence evolution of stars from 1 to with growing accretion rates . The values of are taken equal to a constant fraction of the rates of the mass outflows observed by Churchwell ([CITE]) and Henning ([CITE]). The evolution of the various stellar parameters is given, as well as the evolution of the disc luminosity; electronic tables are provided as a supplement to the articles. Typically, the duration of the accretion phase of massive stars is and there is less than difference in the time necessary to form a 8 or star. If in a young cluster all the proto-stellar cores start to accrete at the same time, we then have a relation between the masses of the new stars and the time t of their appearance. Since we also know the distribution of stellar masses at the end of star formation (IMF), we can derive the star formation history . Interestingly enough, the current IMF implies two peaks of star formation: low mass stars form first and high mass star form later.