WFST Supernovae in the First Year: III. Systematical Study of the Photometric Behavior of Early-phase Core-collapse Supernovae

TL;DR

This study analyzes early-phase core-collapse supernovae with double-peaked light curves, using WFST data and models to infer progenitor properties, suggesting binary evolution as the likely formation channel.

Contribution

It provides a systematic analysis of early shock-cooling emission in supernovae, combining observational data with analytic models to constrain progenitor characteristics and evolution pathways.

Findings

Ejecta masses between 1.1 and 2.6 solar masses.

Progenitors are yellow or blue supergiants with radii 120-300 solar radii.

Binary evolution likely produces these progenitors.

Abstract

We investigate the multiband photometric properties of seven supernovae (SNe) showing double-peaked light-curve evolution and prominent shock-cooling emission, observed by the Wide Field Survey Telescope (WFST) during its first year of operation. By jointly employing an analytic early shock-cooling model and the Arnett radioactive-diffusion model, we fit the bolometric light curves and infer ejecta masses in the range $1.1$-$2.6 M_\odot$, consistent with a transitional population between ultra-stripped supernovae (USSNe) and normal stripped-envelope supernovae (SESNe). The envelope masses are estimated to be $M_{\rm env}=0.1$-$0.4 M_\odot$, while the progenitors are constrained to be yellow or blue supergiants (YSGs/BSGs) with radii of $R=120$-$300 R_\odot$. Using empirical relations, we estimate progenitor luminosities of $L=10^{4.6}$-$10^{4.9} L_\odot$, corresponding to zero-age main-sequence (ZAMS) masses of $8$-$20 M_\odot$. Theoretical models suggest that such progenitors are more naturally produced through binary evolution channels, as single-star evolutionary pathways are unable to yield ejecta masses this low.