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Powerful explosions at Z : 0?

Ekström, Sylvia ; Meynet, Georges ; Hirschi, Raphael ; Maeder, André

In: Proceedings of the International Astronomical Union, 2008, vol. 4, no. S255, p. 194-198

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    Titre
    • Powerful explosions at Z
      0?
    Auteur
    • Ekström, Sylvia. Geneva Observatory, University of Geneva, Maillettes 51 - CH 1290 Sauverny, Switzerland
    • Meynet, Georges. Geneva Observatory, University of Geneva, Maillettes 51 - CH 1290 Sauverny, Switzerland
    • Hirschi, Raphael. University of Keele, Keele, ST5 5BG, UK
    • Maeder, André. Geneva Observatory, University of Geneva, Maillettes 51 - CH 1290 Sauverny, Switzerland
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • Proceedings of the International Astronomical Union, 2008, vol. 4, no. S255, p. 194-198. Cambridge University Press
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:297627
    Summary
    Metal-free stars are assumed to evolve at constant mass because of the very low stellar winds. This leads to large CO-core mass at the end of the evolution, so primordial stars with an initial mass between 25 and 85 M are expected to end as direct black holes, the explosion energy being too weak to remove the full envelope. We show that when rotation enters into play, some mass is lost because the stars are prone to reach the critical velocity during the main sequence evolution. Contrary to what happens in the case of very low- but non zero-metallicity stars, the enrichment of the envelope by rotational mixing is very small and the total mass lost remains modest. The compactness of the primordial stars lead to a very inefficient transport of the angular momentum inside the star, so the profile of Ω(r) is close to Ωr2 = const. As the core contracts, the rotation rate increases, and the star ends its life with a fast spinning core. Such a configuration has been shown to modify substantially the dynamics of the explosion. Where one expected a weak explosion or none at all, rotation might boost the explosion energy and drive a robust supernova. This will have important consequences in the way primordial stars enriched the early Universe