The origin of the Ca-Ti-Cr-Fe-Ni isotopic anomalies in the inclusion EK-1-4-1 of the Allende meteorite

The origin of the correlated Ca-Ti-Cr-Fe-Ni isotopic anomalies in the Ca-Al-rich inclusion of the EK-1-4-1 of the Allende is a longstanding puzzle. The search for a stellar environment which could explain the enrichment of neutron-rich stable Ca-...-Ni isotopes in a self-consistent way requires nuclear physics data far from stability. Recent experimental data have been obtained in the region of the shell closures N = 28 and N = 40, where the possible progenitors of these nuclei are found. Astrophysical network calculations have been updated by including the new beta-decay properties and microscopic predictions of neutron-capture cross sections. Interplay between nuclear structure far from stability and the observed isotopic anomalies is especially evident for the high entropy (S similar or equal to 150) scenario which would characterize the neutrino-driven wind in a type II supernova. (C) 2003 Academie des sciences. Published by Editions scientifiques et medicales Elsevier SAS. All rights reserved.