TY - CHAP
T1 - Models of rotating massive stars
T2 - Impacts of various prescriptions
AU - Meynet, Georges
AU - Ekstrom, Sylvia
AU - Maeder, André
AU - Eggenberger, Patrick
AU - Saio, Hideyuki
AU - Chomienne, Vincent
AU - Haemmerlé, Lionel
PY - 2013/12/1
Y1 - 2013/12/1
N2 - The rotation of stars has many interesting and important consequences for the photometric and chemical evolution of galaxies. Many of the predictions of models of stellar rotation are now compared with observations of surface abundances and velocities, with interferometric studies of fast rotating stars, with internal rotation profiles as they can be deduced by asteroseismology, to cite just a few observational constraints. In this paper, we investigate how the outputs of models depend on the prescriptions used for the diffusion coefficients included in the shellular rotating models. After recalling the various prescriptions found in the literature, we discuss their impacts on the evolutionary tracks and lifetimes of the Main-Sequence (MS) phase, the changes of the surface composition and velocities during the MS phase, the distribution of the core helium lifetime in the blue and red parts of the HR diagram, the extensions of the blue loops, the evolution of the angular momentum of the core, and the synthesis of primary nitrogen in fast-rotating metal-poor massive stars. While some of these outputs depend only slightly on the prescriptions used (for instance, the evolution of the surface velocities), most of them show a significant dependence. The models which best fit the changes of the surface abundances are those computed with the vertical shear diffusion coefficient of Maeder (Astron. Astrophys. 321:134-144, 1997) and the horizontal shear diffusion coefficient by Zahn (Astron. Astrophys. 265:115-132, 1992).
AB - The rotation of stars has many interesting and important consequences for the photometric and chemical evolution of galaxies. Many of the predictions of models of stellar rotation are now compared with observations of surface abundances and velocities, with interferometric studies of fast rotating stars, with internal rotation profiles as they can be deduced by asteroseismology, to cite just a few observational constraints. In this paper, we investigate how the outputs of models depend on the prescriptions used for the diffusion coefficients included in the shellular rotating models. After recalling the various prescriptions found in the literature, we discuss their impacts on the evolutionary tracks and lifetimes of the Main-Sequence (MS) phase, the changes of the surface composition and velocities during the MS phase, the distribution of the core helium lifetime in the blue and red parts of the HR diagram, the extensions of the blue loops, the evolution of the angular momentum of the core, and the synthesis of primary nitrogen in fast-rotating metal-poor massive stars. While some of these outputs depend only slightly on the prescriptions used (for instance, the evolution of the surface velocities), most of them show a significant dependence. The models which best fit the changes of the surface abundances are those computed with the vertical shear diffusion coefficient of Maeder (Astron. Astrophys. 321:134-144, 1997) and the horizontal shear diffusion coefficient by Zahn (Astron. Astrophys. 265:115-132, 1992).
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U2 - 10.1007/978-3-642-33380-4-1
DO - 10.1007/978-3-642-33380-4-1
M3 - Chapter
AN - SCOPUS:84883534567
SN - 9783642333798
T3 - Lecture Notes in Physics
SP - 3
EP - 22
BT - Studying Stellar Rotation and Convection
A2 - Goupil, Mariejo
A2 - Belkacem, Kevin
A2 - Neiner, Coralie
A2 - Green, John
A2 - Lignieres, Francois
ER -