Conférences et séminaires » Séminaire présenté par le Pr KL Kratz, University of Mainz

Séminaire présenté par le Pr KL Kratz, University of Mainz

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Charged-particle and neutron-capture processes in the high-entropy wind of type II supernovae : Comparison of calculations with astronomical observations

Par : Pr KL Kratz, University of Mainz
Date : le 15 juin 2009 à 14h15
Lieu : IPHC, Salle de réunion du bât 27/2

Résumé :

The exact conditions for the supernova high-entropy wind (HEW) as one of the favored sites for the classical rapid neutron-capture "r-process" still cannot be reproduced selfconsistently in state-of-the-art hydrodynamic simulations. Therefore, we have performed large-scale network calculations within a parameterized HEW model to constrain the necessary conditions for a full r-process, and to compare our results with recent astronomical observations. A superposition of entropy trajectories results in an excellent reproduction of the overall Solar-System isotopic abundances (N_r° = N°-N_s) of the "main" r-process elements beyond Sn. For the lighter r-elements, our model supports earlier ideas about a multiplicity of nucleosynthesis processes in the Fe-group region. In the HEW scenario, these suggestions are quantified, and the origin of the "missing" abundances to N_r° is determined to be a primary charged-particle process, thus excluding the historical "weak" neutron-capture r-process component. This explains the recent observations of elemental abundances in metal-poor halo stars. Moreover, we find that in the light trans-Fe region sizeable abundances of classical p-process (e.g. 92,94Mo), s-process (e.g. 96Mo) and r-process (e.g. 100Mo) isotopes are coproduced.

Personne à contacter : Sandrine COURTIN