Theoretical stellar ΔY/ΔO in the early Universe

Ekström, Sylvia ; Meynet, Georges ; Maeder, André ; Chiappini, Cristina ; Georgy, Cyril ; Hirschi, Raphael

In: Proceedings of the International Astronomical Union, 2009, vol. 5, no. S268, p. 447-452

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    Population III stars initiated the chemical enrichment of the Universe. Chemical evolution models seem to favour fast rotators among the very low-metallicity population. When a star rotates fast, it ejects significant quantities of He and its nucleosynthesic products are modified compared to the case without rotation. The value of ΔY/ΔO is explored from a theoretical point of view through stellar models of zero- or very low-metallicity