Evolution of massive stars with new hydrodynamic wind models

A. C. Gormaz-Matamala, M. Curé, G. Meynet, J. Cuadra, J. H. Groh, L. J. Murphy

Submitted on 11 July 2022


Here we present evolutionary models for a set of massive stars, introducing a new prescription for the mass-loss rate obtained from hydrodynamical calculations in which the wind velocity profile, v(r), and the line-acceleration, gline, are obtained in a self consistently way. Replacing mass-loss rates at the Main Sequence stage from the standard Vink's formula by our new recipe, we generate a new set of evolutionary tracks for MZAMS=25,40,70 and 120M and metallicities Z=0.014 (Galactic), Z=0.006 (LMC), and Z=0.002 (SMC). Our new derived formula for mass-loss rate predicts a dependence M˙Za, where a is not longer constant but dependent on the stellar mass: ranging from a0.53 when M120M, to a1.02 when M25M. We found that models adopting the new recipe for M˙ retain more mass during their evolution, which is expressed in larger radii and consequently more luminous tracks over the Hertzsprung-Russell diagram. These differences are more prominent for the cases of MZAMS=70 and 120 M at solar metallicity, where we found self-consistent tracks are 0.1 dex brighter and keep extra mass up to 20 M, compared with the classical models using the previous formulation for mass-loss rate. Moreover, we observed remarkable differences for the evolution of the radionuclide isotope 26Al in the core and the surface of the star. Since M˙sc are weaker than the commonly adopted values for evolutionary tracks, self-consistent tracks predict a later modification in the abundance number of 26Al in the stellar winds. This new behaviour could provide useful information about the real contribution of this isotope from massive stars to the Galactic interstellar medium.


Comment: Accepted for publication in Astronomy & Astrophysics

Subjects: Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Astrophysics of Galaxies