He-shell flashes on the surface of oxygen-neon white dwarfs

TL;DR

This study systematically investigates He-shell flashes on oxygen-neon white dwarfs using stellar evolution models, revealing how accretion rates and initial masses influence nova cycles and nuclear yields, informing binary evolution and neutron star formation.

Contribution

It provides a detailed, systematic analysis of He-shell flashes on ONe white dwarfs across various accretion rates and initial masses, using MESA simulations.

Findings

Mass-retention efficiency increases with WD mass and accretion rate.

Nova cycle duration decreases with WD mass and accretion rate.

Nuclear products vary with accretion scenarios.

Abstract

Accretion induced collapse (AIC) may be responsible for the formation of some interesting neutron star binaries, e.g., millisecond pulsars, intermediate-mass binary pulsars, etc. It has been suggested that oxygen-neon white dwarfs (ONe WDs) can increase their mass to the Chandrasekhar limit by multiple He-shell flashes, leading to AIC events. However, the properties of He-shell flashes on the surface of ONe WDs are still not well understood. In this article, we aim to study He-shell flashes on the surface of ONe WDs in a systematic approach. We investigated the long-term evolution of ONe WDs accreting He-rich material with various constant mass-accretion rates by time-dependent calculations with the stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA), in which the initial ONe WD masses range from 1.1 to 1.35 M . We found that the mass-retention efficiency increases with the ONe WD mass and the mass-accretion rate, whereas both the nova cycle duration and the ignition mass decrease with the ONe WD mass and the mass-accretion rate. We also present the nuclear products in different accretion scenarios. The results presented in this article can be used in the future binary population synthesis studies of AIC events.