Spiral Disk Instability Can Drive Thermonuclear Explosions in Binary White Dwarf Mergers

TL;DR

This paper proposes that a spiral mode instability in the accretion disk during binary white dwarf mergers can trigger thermonuclear explosions, providing a potential explanation for the origin of Type Ia supernovae.

Contribution

It introduces a self-consistent merger model demonstrating how spiral disk instability can lead to supernova explosions in white dwarf mergers.

Findings

Spiral mode instability can induce detonations in white dwarf mergers.

This mechanism explains how mergers can produce Type Ia supernovae.

The model aligns with observational evidence of double-degenerate progenitors.

Abstract

Thermonuclear, or Type Ia supernovae (SNe Ia), originate from the explosion of carbon--oxygen white dwarfs, and serve as standardizable cosmological candles. However, despite their importance, the nature of the progenitor systems that give rise to SNe Ia has not been hitherto elucidated. Observational evidence favors the double-degenerate channel in which merging white dwarf binaries lead to SNe Ia. Furthermore, significant discrepancies exist between observations and theory, and to date, there has been no self-consistent merger model that yields a SNe Ia. Here we show that a spiral mode instability in the accretion disk formed during a binary white dwarf merger leads to a detonation on a dynamical timescale. This mechanism sheds light on how white dwarf mergers may frequently yield SNe Ia.