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128Xe and 130Xe: Testing He-shell burning in AGB stars

R. Reifarth·F. Kaeppeler·F. Voss·K. Wisshak·R. Gallino·M. Pignatari·O. Straniero
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Abstract

The s-process branching at 128I has been investigated on the basis of new, precise experimental (n,g) cross sections for the s-only isotopes 128Xe and 130Xe. This branching is unique, since it is essentially determined by the temperature- and density-sensitive stellar decay rates of 128I and only marginally affected by the specific stellar neutron flux. For this reason it represents an important test for He-shell burning in AGB stars. The description of the branching by means of the complex stellar scenario reveals a significant sensitivity to the time scales for convection during He shell flashes, thus providing constraints for this phenomenon. The s-process ratio 128Xe/130Xe deduced from stellar models allows for a (9+-3)% p-process contribution to solar 128Xe, in agreement with the Xe-S component found in meteoritic presolar SiC grains.

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R. Reifarth, F. Kaeppeler, F. Voss, K. Wisshak, R. Gallino, M. Pignatari, O. Straniero. 2004-05-04. 128Xe and 130Xe: Testing He-shell burning in AGB stars. https://doi.org/10.1086/422206

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