Revealing the progenitor of SN 2021zby through analysis of the $TESS$ shock-cooling light curve

TL;DR

This paper analyzes early TESS observations of SN 2021zby, revealing details about its progenitor star through shock-cooling light curve modeling, and emphasizes the importance of high-cadence, multi-band data for supernova progenitor studies.

Contribution

It provides the first detailed analysis of SN 2021zby’s shock cooling phase using TESS data, constraining its progenitor to be a red or yellow supergiant with specific envelope properties.

Findings

Progenitor likely a red or yellow supergiant with 0.3-3.0 M$_\odot$ envelope mass.

Envelope radius estimated between 50-350 R$_\odot$.

Early, high-cadence, multi-band observations are crucial for progenitor characterization.

Abstract

We present early observations and analysis of the double-peaked Type IIb supernova (SN IIb) 2021zby. $TESS$ captured the prominent early shock cooling peak of SN 2021zby within the first $\sim$10 days after explosion with a 30-minute cadence. We present optical and near-infrared spectral series of SN 2021zby, including three spectra during the shock cooling phase. Using a multi-band model fit, we find that the inferred properties of its progenitor are consistent with a red supergiant or yellow supergiant, with an envelope mass of $\sim$0.3-3.0 M$_\odot$ and an envelope radius of $\sim$50-350$ R_\odot$. These inferred progenitor properties are similar to those of other SNe IIb with double-peak feature, such as SNe 1993J, 2011dh, 2016gkg and 2017jgh. This study further validates the importance of the high cadence and early coverage in resolving the shape of the shock cooling light curve, while the multi-band observations, especially UV, is also necessary to fully constrain the progenitor properties.