Mass-transferring binary stars as progenitors of interacting hydrogen-free supernovae

TL;DR

This study investigates how mass transfer in binary star systems can produce the circumstellar material observed in hydrogen-poor supernovae, suggesting a binary evolution pathway for these explosive events.

Contribution

It introduces detailed binary evolution models showing that mass transfer shortly before core collapse can create the circumstellar environment seen in interacting hydrogen-poor supernovae.

Findings

Mass transfer occurs less than 20,000 years before explosion.

Up to 0.8 solar masses of H-free material can be transferred.

Models qualitatively match properties of Type Ibn SNe.

Abstract

Stripped-envelope supernovae (SNe) are H-poor transients produced at the end of the life of massive stars that previously lost their H-rich envelope. Their progenitors are thought to be donor stars in mass-transferring binary systems, which were stripped of their H-rich envelopes some $10^6$yr before core collapse. A subset of the stripped-envelope SNe exhibit spectral and photometric features indicative of interaction between their ejecta and nearby circumstellar material (CSM). We examine whether mass transfer during, or shortly before, core collapse in massive binary systems can produce the CSM inferred from the observations of interacting H-poor SNe. We select 44 models from a comprehensive grid of detailed binary evolution models in which the mass donors are H-free and explode while transferring mass to a main-sequence companion. We find that in these models, mass transfer starts less than $\sim20$kyr before, and often continues until the core collapse of the donor star. Up to $0.8M_\odot$ of H-free material are removed from the donor star during this phase, which may produce a He-rich circumbinary material. We explore plausible assumptions for its spatial distribution at the time of explosion. When assuming that the CSM accumulates in a circumbinary disk, we find qualitative agreement with the supernova and CSM properties inferred from observed Type Ibn SNe, and to a lesser extent with constraints from Type Icn SNe. We find that our mass transferring stripped envelope SN progenitor models may produce up to $\sim$10% of all stripped envelope supernovae. The binary channel proposed in this work can qualitatively account for the observed key properties and rate of interacting H-poor SNe. Models for the evolution of the circumbinary material and the spectral evolution of exploding progenitors from this channel are needed to further test its significance.