Critical angular velocity and anisotropic mass loss of rotating stars with radiation-driven winds
| Autor: | Michel Rieutord, Bertrand Putigny, D. Gagnier, Corinne Charbonnel, F. Espinosa Lara |
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| Přispěvatelé: | Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Unité d'Amélioration des plantes (CL CLERMONT GENETQ), Institut National de la Recherche Agronomique (INRA), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), ANR-16-CE31-0007,ESRR,Evolution stellaire en rotation rapide(2016) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Angular momentum
FOS: Physical sciences Angular velocity Astrophysics Rotation 01 natural sciences Radiative flux Acceleration stars: rotation 0103 physical sciences Radiative transfer Astrophysics::Solar and Stellar Astrophysics Gravity darkening 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Physics 010308 nuclear & particles physics Computer Science::Information Retrieval Astronomy and Astrophysics stars: early-type Stars Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science Astrophysics::Earth and Planetary Astrophysics [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] stars: mass-loss |
| Zdroj: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, EDP Sciences, 2019, 625, pp.A88. ⟨10.1051/0004-6361/201834599⟩ Astronomy and Astrophysics-A&A, 2019, 625, pp.A88. ⟨10.1051/0004-6361/201834599⟩ |
| ISSN: | 0004-6361 |
| DOI: | 10.1051/0004-6361/201834599⟩ |
| Popis: | The understanding of the evolution of early-type stars is tightly related to that of the effects of rapid rotation. For massive stars, rapid rotation combines with their strong radiation-driven wind. The aim of this paper is to investigate two questions that are prerequisite to the study of the evolution of massive rapidly rotating stars: (i) What is the critical angular velocity of a star when radiative acceleration is significant in its atmosphere? (ii) How do mass and angular momentum loss depend on the rotation rate? To investigate fast rotation, which makes stars oblate, we used the 2D ESTER models and a simplified approach, the $\omega$-model, which gives the latitudinal dependence of the radiative flux in a centrifugally flattened radiative envelope. We find that radiative acceleration only mildly influences the critical angular velocity, at least for stars with masses lower than 40 Msun. We explain this mild reduction of the critical angular velocity compared to the classical Keplerian angular velocity by the combined effects of gravity darkening and a reduced equatorial opacity that is due to the centrifugal acceleration. To answer the second question, we first devised a model of the local surface mass flux, which we calibrated with previously developed 1D models. The discontinuity (the so-called bi-stability jump) included in the $\dot{M}-T_{\rm eff}$ relation of 1D models means that the mass flux of a fast-rotating star is controlled by either a single wind or a two-wind regime. Mass and angular momentum losses are strong around the equator if the star is in the two-wind regime. We also show that the difficulty of selecting massive stars that are viewed pole-on makes detecting the discontinuity in the relation between mass loss and effective temperature also quite challenging. Comment: 16 pages, accepted in Astronomy and Astrophysics |
| Databáze: | OpenAIRE |
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