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Astron. Astrophys. 354, 740-748 (2000)

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The s-process efficiency in massive stars

Marc Rayet 1 and Masa-aki Hashimoto 2

1 Institut d'Astronomie et d'Astrophysique, Université Libre de Bruxelles, CP 226, 1050 Brussels, Belgium
2 Faculty of Science, Department of Physics, Kyushu University, Fukuoka 810-8560, Japan

Received 20 July 1999 / Accepted 2 December 1999


The s-process is studied in the He burning core of a [FORMULA] He star using temperature and density profiles obtained with a standard stellar evolution model and an updated nuclear network. We discuss in detail the s-process efficiency for metallicities [FORMULA] ranging between 1 and [FORMULA] in the light of recent nuclear data. We show that [FORMULA] acts as a powerful neutron poison at low Z although its effect on the s-process yields is still subject to large uncertainties due to our imperfect knowledge of some nuclear reaction rates and of the galactic evolution of nuclei which determine the neutron economy of the s-process.

Key words: nuclear reactions, nucleosynthesis, abundances – stars: abundances – stars: interiors – Galaxy: abundances

Send offprint requests to: M. Rayet

© European Southern Observatory (ESO) 2000

Online publication: February 9, 2000