Browsing by Author "Meynet, G."

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Evolution of massive stars with new hydrodynamic wind models
    (2022) Gormaz-Matamala, A. C.; Cure, M.; Meynet, G.; Cuadra, J.; Groh, J. H.; Murphy, L. J.
    Context. Mass loss through radiatively line-driven winds is central to our understanding of the evolution of massive stars in both single and multiple systems. This mass loss plays a key role in modulating massive star evolution at different metallicities, especially in the case of very massive stars (M* >= 25 M-circle dot).
  • No Thumbnail Available
    Item
    Evolution of rotating massive stars adopting a newer, self-consistent wind prescription at Small Magellanic Cloud metallicity
    (2024) Gormaz-Matamala, A. C.; Cuadra, J.; Ekstrom, S.; Meynet, G.; Cure, M.; Belczynski, K.
    Aims. We aim to measure the impact of our mass-loss recipe in the evolution of massive stars at the metallicity of the Small Magellanic Cloud (SMC). Methods. We used the Geneva-evolution code (GENEC) to run evolutionary tracks for stellar masses ranging from 20 to 85 M-circle dot at SMC metallicity (Z(SMC) = 0.002). We upgraded the recipe for stellar winds by replacing Vink's formula with our self-consistent m-CAK prescription, which reduces the value of the mass-loss rate, (M) over dot, by a factor of between two and six depending on the mass range. Results. The impact of our new [weaker] winds is wide, and it can be divided between direct and indirect impact. For the most massive models (60 and 85 M-circle dot) with (M) over dot greater than or similar to 2 x 10(-7) M-circle dot yr(-1), the impact is direct because lower mass loss make stars remove less envelope, and therefore they remain more massive and less chemically enriched at their surface at the end of their main sequence (MS) phase. For the less massive models (20 and 25 M-circle dot) with (M) over dot less than or similar to 2 x 10(-8) M-circle dot yr(-1), the impact is indirect because lower mass loss means the stars keep high rotational velocities for a longer period of time, thus extending the H-core burning lifetime and subsequently reaching the end of the MS with higher surface enrichment. In either case, given that the conditions at the end of the H-core burning change, the stars will lose more mass during their He-core burning stages anyway. For the case of M-zams = 20-40 M-circle dot, our models predict stars will evolve through the Hertzsprung gap, from O-type supergiants to blue supergiants (BSGs), and finally red supergiants (RSGs), with larger mass fractions of helium compared to old evolution models. New models also sets the minimal initial mass required for a single star to become a Wolf-Rayet (WR) at metallicity Z = 0.002 at M-zams = 85 M-circle dot. Conclusions. These results reinforce the importance of upgrading mass-loss prescriptions in evolution models, in particular for the earlier stages of stellar lifetime, even for Z << Z(circle dot). New values for (M) over dot need to be complemented with upgrades in additional features such as convective-core overshooting and distribution of rotational velocities, besides more detailed spectroscopical observations from projects such as XShootU, in order to provide a robust framework for the study of massive stars at low-metallicity environments.
  • No Thumbnail Available
    Item
    Evolution of rotating massive stars with new hydrodynamic wind models
    (2023) Gormaz-Matamala, A. C.; Cuadra, J.; Meynet, G.; Cure, M.
    Context. Mass loss due to radiatively line-driven winds is central to our understanding of the evolution of massive stars in both single and multiple systems. This mass loss plays a key role in modulating the stellar evolution at different metallicities, particularly in the case of massive stars with M-* >= 25 M-circle dot.