This Master thesis provides a theoretical exploration of the evolution of massive stars, with initial masses 10 <~ Mi/Msun <~ 100. To this aim, the stellar code MESA is used to compute a grid of 27 stellar evolutionary models with initial masses between 15 and 60 Msun, and four choices of the initial metallicity, Z=0.001, 0.006, 0.014 and 0.02. All tracks are evolved from the pre-main sequence til the end of the silicon-burning phase which terminates the sequence of hydrostatic nuclear fusions. For a few selected cases I investigate the effect of rotation, and the impact of the critical nuclear reaction 12C(alpha,gamma)16O. Particular attention is paid to analyze the effect of mass loss on the structure of the most massive stars and their transition through the Wolf-Rayet classes. The second part of the thesis focuses on the pre-supernova structures, mostly in relation to the density and entropy conditions of the central core. The entire grid of models is tested through explodaibility criteria suggested in recent hydro-dynamical calculations, to verify whether the final fate of the star will be a successful explosion or a failed supernova. The results are presented and discussed, also in terms of the compact remnants that may derive from the two channels (neutron star or black hole).

EVOLUTION AND FINAL FATE OF MASSIVE STARS

Volpato, Guglielmo
2020/2021

Abstract

This Master thesis provides a theoretical exploration of the evolution of massive stars, with initial masses 10 <~ Mi/Msun <~ 100. To this aim, the stellar code MESA is used to compute a grid of 27 stellar evolutionary models with initial masses between 15 and 60 Msun, and four choices of the initial metallicity, Z=0.001, 0.006, 0.014 and 0.02. All tracks are evolved from the pre-main sequence til the end of the silicon-burning phase which terminates the sequence of hydrostatic nuclear fusions. For a few selected cases I investigate the effect of rotation, and the impact of the critical nuclear reaction 12C(alpha,gamma)16O. Particular attention is paid to analyze the effect of mass loss on the structure of the most massive stars and their transition through the Wolf-Rayet classes. The second part of the thesis focuses on the pre-supernova structures, mostly in relation to the density and entropy conditions of the central core. The entire grid of models is tested through explodaibility criteria suggested in recent hydro-dynamical calculations, to verify whether the final fate of the star will be a successful explosion or a failed supernova. The results are presented and discussed, also in terms of the compact remnants that may derive from the two channels (neutron star or black hole).
2020-06
58
stellar evolution, massive stars, black holes, supernovae
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12608/22554