Co-Production of Light p-, s- and r-Process Isotopes in the High-Entropy Wind of Type II Supernovae
Abstract
We have performed large-scale nucleosynthesis calculations within the high-entropy-wind (HEW) scenario of Type II supernovae. The primary aim was to constrain the conditions for the production of the classical `p-only' isotopes of the light trans-Fe elements. We find, however, that for electron fractions in the range 0.458 <= Ye <= 0.478, sizeable abundances of p-, s- and r-process nuclei between 64Zn and 98Ru are coproduced in the HEW at low entropies (S <= 100) by a primary charged-particle process after an α-rich freezeout. With the above Ye-S correlation, most of the predicted isotopic abundance ratios within a given element, e.g. 64Zn(p)/70Zn(r) or 92Mo(p)/94Mo(p), as well as of neighboring elements, e.g. 70Ge(s + p)/74Se(p) or 74Se(p)/78Kr(p) agree with the observed Solar-System ratios. Taking the Mo isotopic chain as a particularly challenging example, we show that our HEW model can account for the production of all 7 stable isotopes, from `p-only' 92Mo, via `s-only' 96Mo up to `r-only' 100Mo. Furthermore, our model is able to reproduce the isotopic composition of Mo in presolar SiC X-grains.
- Publication:
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Publications of the Astronomical Society of Australia
- Pub Date:
- September 2009
- DOI:
- arXiv:
- arXiv:0906.1076
- Bibcode:
- 2009PASA...26..194F
- Keywords:
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- nuclear reactions;
- nucleosynthesis;
- abundances;
- stars: winds;
- outflows;
- supernovae: general;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 10 pages, 2 figures