Co-Production of Light p-, s- and r-Process Isotopes in the High-Entropy Wind of Type II Supernovae

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 <= Y-e <= 0.478, sizeable abundances of p-, s- and r-process nuclei between Zn-64 and Ru-98 are coproduced in the HEW at low entropies (S <= 100) by a primary charged-particle process after an alpha-rich freezeout. With the above Y-e-S correlation, most of the predicted isotopic abundance ratios within a given element, e.g. Zn-64(p)/Zn-70(r) or Mo-92(p)/Mo-94(p), as well as of neighboring elements, e.g. Ge-70(s + p)/Se-74(p) or Se-74(p)/Kr-78(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' Mo-92, via 's-only' Mo-96 up to 'r-only' Mo-100. Furthermore, our model is able to reproduce the isotopic composition of Mo in presolar SiC X-grains.