München 2006 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 31: Kern- und Teilchen-Astrophysik

HK 31.3: Gruppenbericht

Mittwoch, 22. März 2006, 15:00–15:30, E

The weak s process in massive stars — •Michael Heil — Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe

Over the last decades, considerable effort in experimental nuclear astrophysics, stellar modelling, and observations led to an improved understanding of various nucleosynthesis scenarios. This is particularly true for the main s process in low-mass AGB stars, which is largely responsible for the production of about half of the elemental abundances in the mass range 90<A<209. The weak s process, which produces elements with A<90 is, however, much less understood. Since this process operates in massive stars and, therefore determines the composition of the supernova progenitors, it is ultimately linked with the abundance contributions of explosive nucleosynthesis. More accurate neutron capture cross sections in the mass range 56<A<90 are indispensable for a meaningful comparison of model predictions with observational data. Recent experiments have shown that many neutron capture cross sections in this mass range are systematically overestimated. New results for neutron capture cross sections on light and medium mass nuclei will be presented and the influence on the production rate in massive stars will be discussed.