Modelling the composition of a young star cluster ejecta

Abstract

We have computed with a fine time grid the evolution of the elemental abundances of He, C, N and O ejected by a young (t < 20 Myr) and massive (M$=10^{6}$\,\Msun) coeval stellar cluster with a Salpeter initial mass function (IMF) over a wide range of initial abundances. Our computations incorporate the mass loss from massive stars (M >30 Msun) during their wind phase including the Wolf-Rayet phase and the ejecta from the core collapse supernovae. We find that during the Wolf-Rayet phase (t <5 Myr) the cluster ejecta composition suddenly becomes vastly over-abundant in N for all initial abundances and in He, C and O for initial abundances higher than 1/5th Solar. The C and O abundance in the cluster ejecta can reach over 50 times the solar value with important consequences for the chemical and hydrodynamical evolution of the surrounding ISM.