Interstellar potassium and argon

Abstract

Isotopic anomalies are calculated in K and Ar that will be expected to be carried in interstellar grains. Special attention is given to the supernova condensates that precipitate during the expansion of the explosive oxygen-burning zone of the interior, because that is where K-39, K-41 and Ar-36, Ar-38 find their natural origins. Expectations are given for K-Ar ages in excess of the solar age in accumulations of presolar grains, and for K anomalies in Ca-rich mineral within Allende inclusions, because experiments searching for such effects are currently underway. Attention is also given to predictions of excess Ar-36 owing to extinct Cl-36 within presolar grains, and to descriptions of new correlations that can confirm its existence.