Mass retention efficiencies of He accretion onto carbon-oxygen white dwarfs and type Ia supernovae

TL;DR

This study investigates the mass retention efficiencies of helium nova outbursts on carbon-oxygen white dwarfs and their potential to produce Type Ia supernovae, providing new simulation data and insights into supernova progenitors.

Contribution

The paper presents detailed simulations of helium nova outbursts across various white dwarf masses, revealing lower retention efficiencies and their implications for supernova rates and explosion modeling.

Findings

He nova outbursts can increase WD mass to Chandrasekhar limit

Simulated retention efficiencies are lower than previous estimates

He nova outbursts can trigger explosive carbon burning in WDs

Abstract

Type Ia supernovae (SNe Ia) play a crucial role in studying cosmology and galactic chemical evolution. They are thought to be thermonuclear explosions of carbon-oxygen white dwarfs (CO WDs) when their masses reach the Chandrasekar mass limit in binaries. Previous studies have suggested that He novae may be progenitor candidates of SNe Ia. However, the mass retention efficiencies during He nova outbursts are still uncertain. In this article, we aim to study the mass retention efficiencies of He nova outbursts and to investigate whether SNe Ia can be produced through He nova outbursts. Using the stellar evolution code Modules for Experiments in Stellar Astrophysics, we simulated a series of multicycle He-layer flashes, in which the initial WD masses range from 0.7 to 1.35 Msun with various accretion rates. We obtained the mass retention efficiencies of He nova outbursts for various initial WD masses, which can be used in the binary population synthesis studies. In our simulations, He nova outbursts can increase the mass of the WD to the Chandrasekar mass limit and the explosive carbon burning can be triggered in the center of the WD; this suggests that He nova outbursts can produce SNe Ia. Meanwhile, the mass retention efficiencies in the present work are lower than those of previous studies, which leads to a lower birthrates of SNe Ia through the WD + He star channel. Furthermore, we obtained the elemental abundances distribution at the moment of explosive carbon burning, which can be used as the initial input parameters in studying explosion models of SNe Ia.