2015ApJ...803..101P

The recent discovery that the Fe-K line luminosities and energy centroids observed in nearby supernova remnants are a strong discriminant of both progenitor type and circumstellar environment has implications for our understanding of supernova progenitor evolution. Using models for the chemical composition of core-collapse supernova (CCSN) ejecta, we model the dynamics and thermal X-ray emission from shocked ejecta and circumstellar material, modeled as an r^–2 wind, to ages of 3000 yr. We compare the X-ray spectra expected from these models to observations made with the Suzaku satellite. We also model the dynamics and X-ray emission from Type Ia progenitor models. We find a clear distinction in Fe-K line energy centroid between core-collapse and Type Ia models. The CCSN models predict higher Fe-K line centroid energies than the Type Ia models, in agreement with observations. We argue that the higher line centroids are a consequence of the increased densities found in the circumstellar environment created by the expansion of the slow-moving wind from the massive progenitors.