Speaker
Description
A massive star explodes as a core-collapse supernovae at the end of life and the explosion can be observed as a supernova remnant (SNR) over up to about ten thousand years. The elemental abundances observed in SNRs provide important clues to both nucleosynthesis in pre-supernova evolution and the supernova explosion. Recent observations of Cassiopeia A (Cas A), which is one of the best-studied SNR, with XRISM/Resolve have revealed detailed abundances of various elements, including odd-Z elements such as Cl and K (XRISM Collaboration 2025; Sato et al. 2026). These observations point out the possibility that the progenitor of Cas A experienced a shell merger caused by convective mixing shortly before core collapse. However, it remains unclear whether the observed elemental abundances originate from pre-supernova evolution or explosive nucleosynthesis, which burning they reflect, and whether each observed region can be reproduced with a single burning layer.
In this study, we calculate 1D stellar evolution and supernova nucleosynthesis and compare the results with the elemental abundance measurements of Cas A. We focus particularly on the newly observed odd-Z elements, including Cl and K, as well as Fe-peak elements, to investigate the relative contributions of pre-supernova evolution and explosive nucleosynthesis.
Our results suggest that the observed elemental abundance ratios cannot be explained by a single burning layer and may require contributions from multiple burning layers.
In this talk, we discuss the origin of the elemental abundances observed in different regions of Cas A.
| Category | Theory |
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