Using CSST and ejecta-wind interaction in type II-P supernovae to constrain the wind-mass loss of red supergiant stars

¹ Yunnan Observatories, Chinese Academy of Sciences (CAS), Kunming 650216, P.R. China
² Key Laboratory for the Structure and Evolution of Celestial Objects, CAS, Kunming 650216, P.R. China
³ University of Chinese Academy of Sciences, Beijing 100049, P.R. China
⁴ International Centre of Supernovae, Yunnan Key Laboratory, Kunming 650216, P.R. China
⁵ Institut d’Astrophysique de Paris, CNRS-Sorbonne Université, 98 bis boulevard Arago, 75014 Paris, France

Received: 29 December 2023
Accepted: 30 May 2024

Abstract

The properties of H-rich, type II-plateau supernova (SN II-P) progenitors remain uncertain, and this is primarily due to the complexities associated with red supergiant (RSG) mass loss. Recent studies have suggested that the interaction of the ejecta with a standard RSG wind should produce unambiguous signatures in the optical (e.g., a broad, boxy Hα profile) and in the UV (especially Ly α and Mg IIλλ 2795,  2802) a few years following the explosion. Such features are expected to be generic in all SNe II-P and can be utilized to constrain RSG winds. Here, we investigate the possibility of detecting late-time (0.3–10 years since explosion) SNe II-P in the NUV with the China Space Station Telescope (CSST). Convolving the existing model spectra of ejecta-wind interactions in SNe II-P with the transmission functions of the CSST, we calculated the associated multiband light curves, in particular, the NUV (255 nm–317 nm) band, as well as the NUV − r color. We find that the CSST will be able to detect the NUV radiation associated with ejecta-wind interaction for hundreds SNe II-P out to a few hundred Mpc over its ten-year main sky survey. The CSST will therefore provide a sizable sample of SNe II-P with the NUV signatures of ejecta-wind interaction. This will be helpful for understanding the mass loss history of SN II-P progenitors and their origins.