An environmental analysis of the Type Ib SN 2019yvr and the possible presence of an inflated binary companion

TL;DR

This study analyzes the environment and progenitor system of SN 2019yvr, suggesting a binary system with an inflated companion, and highlights the importance of binary interactions and mass loss in low-mass core-collapse supernovae.

Contribution

It provides the first possible direct detection of a binary companion for a Type Ib SN progenitor and links binary interaction to supernova evolution.

Findings

Progenitor likely from the oldest star formation population with ~10.4 M_sun.

Pre-explosion SED indicates a hot progenitor and a cool inflated YHG companion.

SN 2019yvr shows a transition from Type Ib to IIn due to CSM interaction.

Abstract

SN 2019yvr is the second Type Ib supernova (SN) with a possible direct detection of its progenitor (system); however, the spectral energy distribution (SED) of the pre-explosion source appears much cooler and overluminous than an expected helium-star progenitor. Using Hubble Space Telescope (HST) images and MUSE integral-field-unit (IFU) spectroscopy, we find the SN environment contains three episodes of star formation; the low ejecta mass suggests the SN progenitor is most likely from the oldest population, corresponding to an initial mass of 10.4$^{+1.5}_{-1.3}$ $M_\odot$. The pre-explosion SED can be reproduced by two components, one for the hot and compact SN progenitor and one for a cool and inflated yellow hypergiant (YHG) companion that dominates the brightness. Thus, SN 2019yvr could possibly be the first Type Ib/c SN for which the progenitor's binary companion is directly detected on pre-explosion images. Both the low progenitor mass and the YHG companion suggest significant binary interaction during their evolution. Similar to SN 2014C, SN 2019yvr exhibits a metamorphosis from Type Ib to Type IIn, showing signatures of interaction with hydrogen-rich circumstellar material (CSM) at >150 days; our result supports enhanced pre-SN mass loss as an important process for hydrogen-poor stars at the low mass end of core-collapse SN progenitors.