BINARY SYSTEMS OF CORE-COLLAPSE SUPERNOVAE POLLUTING A GIANT COMPANION

Abstract

We examine binary systems where the more massive star, the primary, explodes as a core collapse supernova (CCSN) the secondary star is already a giant that intercepts a large fraction of the ejecta. The ejecta might pollute the secondary star with newly synthesized elements such as calcium. We use Modules for Experiments in Stellar Astrophysics (MESA) to calculate the evolution of such SN-polluted giant (SNPG) binaries. We estimate that on average at any given time tens of SNPGs are present in the Galaxy, and $\approx 10$ SNPG objects are present in the Magellanic Clouds. We speculate that the high calcium abundance of the recently discovered evolved star HV2112 in the Small Magellanic Cloud might be the result of an SNPG with a super AGB stellar secondary of a mass $\approx 9 M_\odot$. This rare SNPG scenario is an alternative explanation to HV2112 being a Thorne-{\.Z}ytkow object (TZO).