Progenitor constraint using line ratios of the CNO elements in supernova remnants

Unveiling the nature of progenitors is crucial for understanding the origin and the mechanism of core-collapse and thermonuclear supernovae (SNe). While several methods have been developed to derive stellar properties so far, many questions remain poorly understood. In this paper we demonstrate an observational approach to constrain progenitors of supernova remnants (SNRs) using abundances of carbon (C), nitrogen (N), and oxygen (O) in shock-heated circumstellar material (CSM). Our calculations with stellar evolution codes indicate that a total amount of these CNO elements will provide a more sensitive determination of the progenitor masses than the conventional method based on ejecta abundances. If the CNO lines (particularly those of C and N) are detected and measured their abundance ratios accurately, they can provide relatively robust constraint on the progenitor mass (and in some cases the rotation velocity) of SNRs. Since our method requires a better energy resolution and larger effective area in the soft X-ray band ($<1$~keV), XRISM launched on September 7, 2023 and next-generation microcalorimeter missions such as Athena, Lynx, LEM, and HUBS will bring a new insight into link between the progenitors and their remnants.