Constraints on the Progenitor System of SN 2016gkg from a Comprehensive Statistical Analysis

TL;DR

This study uses Bayesian inference with stellar models to analyze the progenitor system of SN 2016gkg, finding a moderate probability of a binary origin and highlighting the importance of statistical methods in understanding supernova progenitors.

Contribution

The paper introduces a comprehensive Bayesian analysis combining stellar models and observational data to constrain the progenitor system of a Type IIb supernova, emphasizing the role of statistical inference.

Findings

Binary progenitors have smaller hydrogen envelopes than single stars.

Probability of binary progenitor is 22% with luminosity and temperature constraints.

Probability increases to 44% when including hydrogen-envelope mass and radius constraints.

Abstract

Type IIb supernovae (SNe) present a unique opportunity for understanding the progenitors of stripped-envelope (SE) SNe as the stellar progenitor of several Type IIb SNe have been identified in pre-explosion images. In this paper, we use Bayesian inference and a large grid of non-rotating solar-metallicity single and binary stellar models to derive the associated probability distributions of single and binary progenitors of the Type IIb SN 2016gkg using existing observational constraints. We find that potential binary star progenitors have smaller pre-SN hydrogen-envelope and helium-core masses than potential single-star progenitors typically by 0.1 Msun and 2 Msun, respectively. We find that, a binary companion, if present, is a main-sequence or red-giant star. Apart from this, we do not find strong constraints on the nature of the companion star. We demonstrate that the range of progenitor helium-core mass inferred from observations could help improve constraints on the progenitor. We find that the probability that the progenitor of SN 2016gkg was a binary is 22% when we use constraints only on the progenitor luminosity and effective temperature. Imposing the range of pre-SN progenitor hydrogen-envelope mass and radius inferred from SN light-curves the probability the progenitor is a binary increases to 44%. However, there is no clear preference for a binary progenitor. This is in contrast to binaries being the currently favored formation channel for Type IIb SNe. Our analysis demonstrates the importance of statistical inference methods to constrain progenitor channels.