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Issue A&A
Volume 429, Number 2, January II 2005
Page(s) 613 - 624
Section Stellar structure and evolution
DOI 10.1051/0004-6361:20041757



A&A 429, 613-624 (2005)
DOI: 10.1051/0004-6361:20041757

New estimates of the contribution of Wolf-Rayet stellar winds to the Galactic  $\mathsf}$Al

A. Palacios1, G. Meynet2, C. Vuissoz3, J. Knödlseder4, D. Schaerer2, 5, M. Cerviño6 and N. Mowlavi7

1  Institut d'Astronomie et d'Astrophysique de l'Université Libre de Bruxelles, 226 Bd du Triomphe, 1050 Brussels, Belgium
    e-mail: palacios@astro.ulb.ac.be
2  Observatoire de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
    e-mail: Georges.Meynet@obs.unige.ch
3  Laboratoire d'Astrophysique de l'EPFL - Observatoire, 1290 Chavannes-des-Bois, Switzerland
4  Centre d'Étude Spatiale des Rayonnements - 9, Av. du Colonel Roche, BP 4346, 31028 Toulouse Cedex 4, France
5  Laboratoire d'Astrophysique de Toulouse-Tarbes, 14 avenue Edouard Belin, 31400 Toulouse, France
6  Instituto de Astrofísica de Andalucía (CSIC) - Camino bajo de Huétor 24, Apdo. 3004, 18080 Granada, Spain
7  INTEGRAL Science Data Center, Chemin d'Ecogia 16, 1290 Versoix, Switzerland

(Received 30 July 2004 / Accepted 13 August 2004 )

Abstract
We present new yields of  $^{\rm Al}$ from Wolf-Rayet stellar winds based on rotating stellar models which account well for numerous observed properties of massive stars. We study the impacts on the yields of a change of initial mass, metallicity and initial rotation velocity. We also consider the effects of a change of mass loss rates during the Wolf-Rayet phase.

We show that for surface rotation velocities during the core H-burning phase matching to the observed ones, the quantity of  $^{\rm Al}$ ejected by a star of a given initial mass and metallicity is roughly doubled when the effects of rotation are taken into account. The metallicity dependence of the yield is, on the other hand, very similar to that obtained from non-rotating models.

We estimate that at least about 20% to 50% (e.g. ~ $0.6{-}1.4~M_\odot$) of the live  $^{\rm Al}$ detected in the Milky-Way originates from Wolf-Rayet stellar winds. We show the importance of a good knowledge of the present metallicity gradient and star formation rate in our galaxy for modeling both the variation of the  $^{\rm Al}$ surface density with the galactocentric distance and the global contribution of the Wolf-Rayet stellar winds to the present galactic mass of  $^{\rm Al}$.


Key words: nuclear reactions, nucleosynthesis, abundances -- stars: rotation -- Galaxy: abundances -- stars: Wolf-Rayet -- stars: abundances

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© ESO 2004


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