Interstellar diamond xenon and timescales of supernova ejecta

The composition of isotopically anomalous Xe-H carried by interstellar diamonds in meteorites can be quantitatively explained by standard r-process nucleosynthesis, if a separation of xenon from iodine and tellurium precursors is accomplished on a timescale of a few hours after termination of the process. Such a separation process would also qualitatively account for features of Xe-L and Kr-H, and the low abundance of non-noble gas trace elements. Possible mechanisms include precondensation, loss from the diamonds upon beta-decay of precursors, and charge state separation. Whether one of these mechanisms is a viable option in supernova environments on the required timescale remains to be investigated.