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ABSTRACT The most massive stars provide an essential source of recycled material for young clusters and galaxies. While very massive stars (VMSs, M>100 $$\rm {\rm M}_{\odot }$$) are relatively rare compared to O stars, they lose disproportionately large amounts of mass already from the onset of core H-burning. VMS have optically thick winds with elevated mass-loss rates in comparison to optically thin standard O-star winds. We compute wind yields and ejected masses on the main sequence, and we compare enhanced mass-loss rates to standard ones. We calculate solar metallicity wind yields from MESA stellar evolution models in the range 50–500 $$\rm {\rm M}_{\odot }$$, including a large nuclear network of 92 isotopes, investigating not only the CNO-cycle, but also the Ne–Na and Mg–Al cycles. VMS with enhanced winds eject 5–10 times more H-processed elements (N, Ne, Na, Al) on the main sequence in comparison to standard winds, with possible consequences for observed anticorrelations, such as C–N and Na–O, in globular clusters. We find that for VMS 95 per cent of the total wind yields is produced on the main sequence, while only ∼ 5 per cent is supplied by the post-main sequence. This implies that VMS with enhanced winds are the primary source of 26Al, contrasting previous works where classical Wolf–Rayet winds had been suggested to be responsible for galactic 26Al enrichment. Finally, 200 $$\rm {\rm M}_{\odot }$$ stars eject 100 times more of each heavy element in their winds than 50 $$\rm {\rm M}_{\odot }$$ stars, and even when weighted by an IMF their wind contribution is still an order of magnitude higher than that of 50 $$\rm {\rm M}_{\odot }$$ stars.
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This content will become publicly available on July 1, 2026
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 withZ, 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.
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- Award ID(s):
- 1927130
- PAR ID:
- 10649130
- Publisher / Repository:
- EDP Sciences
- Date Published:
- Journal Name:
- Astronomy & Astrophysics
- Volume:
- 699
- ISSN:
- 0004-6361
- Page Range / eLocation ID:
- A71
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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