The impact of wind mass loss on nucleosynthesis and yields of very massive stars at low metallicity

The chemical feedback from stellar winds in low metallicity ( Z ) environments is key to understanding the evolution of globular clusters and the early Universe. With a disproportionate amount of mass lost from the most massive stars ( M > 100 M ⊙ ) and an excess of such stars expected at the lowest metallicities, their contribution to the enrichment of the early pristine clusters could be significant. In this work, we examine the effect of mass loss at low metallicity on the nucleosynthesis and wind yields of (very) massive stars. We calculated stellar models with initial masses ranging from 30 to 500 M ⊙ during core hydrogen and helium burning phases at four metallicities ranging from 20% Z ⊙ down to 1% Z ⊙ . We provide the ejected masses and net yields for each grid of models. While mass-loss rates decrease with Z , we find that not only are wind yields significant, but the nucleosynthesis is also altered due to the change in central temperatures, and therefore it also plays a role. We find that 80–300 M ⊙ models can produce large quantities of Na-rich and O-poor material, which is relevant for the observed Na-O anti-correlation in globular clusters.