The thermonuclear production of F by Wolf-Rayet stars revisited

¹ Institut d'Astronomie et d'Astrophysique, Université Libre de Bruxelles, Bd. du Triomphe CP 226, 1050 Brussels, Belgium e-mail: palacios@astro.ulb.ac.be
² Geneva Observatory, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland

Received: 27 April 2005
Accepted: 19 July 2005

Abstract

New models of rotating and non-rotating stars are computed for initial masses between 25 and 120  and for metallicities , 0.008, 0.020, and 0.040 with the aim of reexamining the wind contribution of Wolf-Rayet (WR) stars to the ¹⁹F enrichment of the interstellar medium. Models with an initial rotation velocity   are found to globally eject less ¹⁹F than the non-rotating models. We compare our new predictions with those of Meynet & Arnould (2000, A&A, 355, 176), and demonstrate that the ¹⁹F yields are very sensitive to the still uncertain rate and to the adopted mass loss rates. Using the recommended mass loss rate values that take into account the clumping of the WR wind and the NACRE reaction rates, when available, we obtain WR ¹⁹F yields that are significantly lower than predicted by Meynet & Arnould (2000, A&A, 355, 176) and that would make WR stars non-important contributors to the galactic ¹⁹F budget. In view, however, of the large nuclear and mass loss rate uncertainties, we consider that the question of the WR contribution to the galactic ¹⁹F remains quite open.