Accreting White Dwarfs: Effect of WD Composition on Helium Ignition During Slow Accretion

Abstract

Understanding the explosion mechanism of type Ia supernova is among the most challenging issues in astrophysics. Accretion of matter on a carbon-oxygen white dwarf from a companion star is one of the most important keys in this regard. Our aim is to study the effects of WD composition on various parameters during the accretion of helium rich matter at a slow rate. We have used the computer simulation code Modules for Experiments in Stellar Astrophysics (MESA) to understand the variations in the properties such as specific heat (\textit{$C_P$}) and degeneracy parameter (\textit{$\eta$}). The profile of specific heat shows a discontinuity and that of the degeneracy parameter shows a dip near the ignition region. As expected, the size of WD decreases and \textit{g} increases during the accretion. However, a red-giant-like expansion is observed after the rapid ignition towards the end. Our study explains the reason behind the delay in onset of helium ignition due to the difference in carbon abundance in a CO-WD. We find that white dwarfs of the lower abundance of carbon accrete slightly longer before the onset of helium ignition.

5 pages, 4 figures, 3 tables. arXiv admin note: substantial text overlap with arXiv:2111.13141

References in corpus (8)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• On the Origin of the Type Ia Supernova Width-Luminosity Relation
• He-Accreting WDs: accretion regimes and final outcomes
• He-accreting carbon-oxygen white dwarfs and type Ia supernovae
• A hot subdwarf-white dwarf super-Chandrasekhar candidate supernova Ia progenitor
• The Magnetized White Dwarf + Helium star Binary Evolution with Accretion-induced Collapse
• Type Ia Supernova Models and Progenitor Scenarios