# Observational Evidence for High Neutronization in Supernova Remnants: Implications for Type Ia Supernova Progenitors

 dc.contributor.author Martínez-Rodríguez, Héctor dc.contributor.author Badenes, Carles dc.contributor.author Yamaguchi, Hiroya dc.contributor.author Bravo, Eduardo dc.contributor.author Timmes, F. X. dc.contributor.author Miles, Broxton J. dc.contributor.author Townsley, Dean M. dc.contributor.author Piro, Anthony L. dc.contributor.author Mori, Hideyuki dc.contributor.author Andrews, Brett dc.contributor.author Park, Sangwook dc.date.accessioned 2018-08-24T13:17:22Z dc.date.available 2018-08-24T13:17:22Z dc.date.issued 2017-07-01 dc.identifier.citation Martínez-Rodríguez, H., et al. (2017): Observational Evidence for High Neutronization in en_US Supernova Remnants: Implications for Type Ia Supernova Progenitors. The Astrophysical Journal, 843(1). dc.identifier.uri http://ir.ua.edu/handle/123456789/3768 dc.description.abstract The physical process whereby a carbon–oxygen white dwarf explodes as a Type Ia supernova (SN Ia) remains en_US highly uncertain. The degree of neutronization in SN Ia ejecta holds clues to this process because it depends on the mass and the metallicity of the stellar progenitor, and on the thermodynamic history prior to the explosion. We report on a new method to determine ejecta neutronization using Ca and S lines in the X-ray spectra of Type Ia supernova remnants (SNRs). Applying this method to Suzaku data of Tycho, Kepler, 3C 397, and G337.2−0.7 in the Milky Way, and N103B in the Large Magellanic Cloud, we find that the neutronization of the ejecta in N103B is comparable to that of Tycho and Kepler, which suggests that progenitor metallicity is not the only source of neutronization in SNe Ia. We then use a grid of SN Ia explosion models to infer the metallicities of the stellar progenitors of our SNRs. The implied metallicities of 3C 397, G337.2−0.7, and N103B are major outliers compared to the local stellar metallicity distribution functions, indicating that progenitor metallicity can be ruled out as the origin of neutronization for these SNRs. Although the relationship between ejecta neutronization and equivalent progenitor metallicity is subject to uncertainties stemming from the 12C + 16O reaction rate, which affects the Ca/S mass ratio, our main results are not sensitive to these details. dc.format.mimetype application/pdf en_US dc.subject atomic data en_US dc.subject nuclear reactions, nucleosynthesis, abundances en_US dc.subject ISM: supernova remnants en_US dc.subject X-rays: ISM en_US dc.title Observational Evidence for High Neutronization in Supernova Remnants: Implications for Type Ia Supernova Progenitors en_US dc.type text en_US
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