A Nucleosynthetic Origin for the Southwestern Fe-rich Structure in Kepler's Supernova Remnant

Author/Creator ORCID

Date

2020-01-08

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Citation of Original Publication

Sato, Toshiki et al. “A Nucleosynthetic Origin for the Southwestern Fe-Rich Structure in Kepler’s Supernova Remnant.” The Astrophysical Journal 890.2 (2020): 104. Crossref. Web.,10.3847/1538-4357/ab6aa2

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This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.

Subjects

Abstract

Chandra X-ray observations of Kepler’s supernova remnant indicate the existence of a high speed Fe-rich ejecta structure in the southwestern region. We report strong K-shell emission from Fe-peak elements (Cr, Mn, Fe, Ni), as well as Ca, in this Fe-rich structure, implying that those elements could be produced in the inner area of the exploding white dwarf. We found Ca/Fe, Cr/Fe, Mn/Fe and Ni/Fe mass ratios of 1.0–4.1%, 1.0–4.6%, 1–11% and 2–30%, respectively. In order to constrain the burning regime that could produce this structure, we compared these observed mass ratios with those in 18 one-dimensional Type Ia nucleosynthesis models (including both near-MCh and sub-MCh explosion models). The observed mass ratios agree well with those around the middle layer of incomplete Si-burning in Type Ia nucleosynthesis models with a peak temperature of ∼(5.0–5.3)×10⁹ K and a high metallicity, Z > 0.0225. Based on our results, we infer the necessity for some mechanism to produce protruding Fe-rich clumps dominated by incomplete Si-burning products during the explosion. We also discuss the future perspectives of X-ray observations of Fe-rich structures in other Type Ia supernova remnants.