Grids of stellar models with rotation. I: Models from 0.8 to 120 M⊙ at solar metallicity (Z = 0.014)

Article Article scientifique Article Grids of stellar models with rotation. I: Models from 0.8 to 120 M⊙ at solar metallicity (Z = 0.014) eng 2012 author Ekström Sylvia 0000-0002-2564-5660 514725 author Georgy Cyril 0000-0003-2362-4089 540258 author Eggenberger Patrick 504578 author Meynet Georges 22422 author Mowlavi Nami 109031 author Wyttenbach Aurélien 699373 author Granada Anahi 731820 author Decressin Thibaut 135402 author Hirschi Raphael 527684 author Frischknecht U. author Charbonnel Corinne 22674 author Maeder André 25143 1-18 10.1051/0004-6361/201117751 0004-6361 http://www.aanda.org/10.1051/0004-6361/201117751 Aims. Many topical astrophysical research areas, such as the properties of planet host stars, the nature of the progenitors of different types of supernovae and gamma ray bursts, and the evolution of galaxies, require complete and homogeneous sets of stellar models at different metallicities in order to be studied during the whole of cosmic history. We present here a first set of models for solar metallicity, where the effects of rotation are accounted for in a homogeneous way. Methods. We computed a grid of 48 different stellar evolutionary tracks, both rotating and non-rotating, at Z = 0.014, spanning a wide mass range from 0.8 to 120 M⊙. For each of the stellar masses considered, electronic tables provide data for 400 stages along the evolutionary track and at each stage, a set of 43 physical data are given. These grids thus provide an extensive and detailed data basis for comparisons with the observations. The rotating models start on the zero-age main sequence (ZAMS) with a rotation rate υini/υcrit = 0.4. The evolution is computed until the end of the central carbon-burning phase, the early asymptotic giant branch (AGB) phase, or the core helium-flash for, respectively, the massive, intermediate, and both low and very low mass stars. The initial abundances are those deduced by Asplund and collaborators, which best fit the observed abundances of massive stars in the solar neighbourhood. We update both the opacities and nuclear reaction rates, and introduce new prescriptions for the mass-loss rates as stars approach the Eddington and/or the critical velocity. We account for both atomic diffusion and magnetic braking in our low-mass star models. Results. The present rotating models provide a good description of the average evolution of non-interacting stars. In particular, they reproduce the observed main-sequence width, the positions of the red giant and supergiant stars in the Hertzsprung-Russell (HR) diagram, the observed surface compositions and rotational velocities. Very interestingly, the enhancement of the mass loss during the red-supergiant stage, when the luminosity becomes supra-Eddington in some outer layers, help models above 15−20 M⊙ to lose a significant part of their hydrogen envelope and evolve back into the blue part of the HR diagram. This result has interesting consequences for the blue to red supergiant ratio, the minimum mass for stars to become Wolf-Rayet stars, and the maximum initial mass of stars that explode as type II−P supernovae. Stars: general Stars: evolution Stars: massive Stars: low-mass Stars: rotation Dewey 520 26 Département d'astronomie 12 false 866 Direction de recherche "Physique stellaire" Astronomy & astrophysics 537 A146 1c08c61a-a3c1-4078-b499-36711aef266c Article (Published version) Public Ekstrom2012a.pdf 1099489 application/pdf openAccess Faculté des sciences / Département d'astronomie

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Grids of stellar models with rotation. I: Models from 0.8 to 120 M⊙ at solar metallicity (Z = 0.014)	Astronomy & astrophysics			2012	396	1,537

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Granada, Anahi