Origin of anomalous Xe-H in nanodiamond stardust
- Max-Planck-Institut für Chemie, Otto-Hahn-Institut, D-55128 Mainz, Germany and Fachbereich Chemie, Pharmazie und Geowissenschaften, Universitat Mainz, Mainz (United States)
- Max-Planck-Institut für Chemie, Otto-Hahn-Institut, D-55128 Mainz, Germany and Zentrum für Astronomie der Universität Heidelberg, D-69120 Heidelberg (Germany)
- Max-Planck-Institut für Chemie, Otto-Hahn-Institut, D-55128 Mainz (Germany)
- II. Physikalisches Institut, Univ. Giessen, D-35392 Giessen (Germany)
Still today, the nucleosynthesis origin of Xe-H in presolar nanodiamonds is far from understood. Historically possible explanations were proposed by a secondary “neutron-burst” process occurring in the He- or C/O-shells of a type-II supernova (SN-II), which are, however, not fully convincing in terms of modern nucleosynthesis conditions. Therefore, we have investigated Xe isotopic abundance features that may be diagnostic for different versions of a classical, primary r-process in high-entropy-wind (HEW) ejecta of core-collapse SN-II. We report here on parameter tests for non-standard r-process variants, by varying electron abundances (Y{sub e}), ranges of entropies (S) and expansion velocities (V{sub exp}) with their correlated neutron-freezeout times (τ(freeze)) and temperatures (T{sub 9}(freeze)). From this study, we conclude that a best fi to the measured Xe-H abundance ratios {sup i}Xe/{sup 136}Xe can be obtained with the high-S “main” component of a “cold” r-process variant.
- OSTI ID:
- 22280413
- Journal Information:
- AIP Conference Proceedings, Vol. 1595, Issue 1; Conference: 7. European summer school on experimental nuclear astrophysics, Santa Tecla, Sicily (Italy), 15-17 Sep 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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