Type IA supernovae from very long delayed explosion of core - WD merger

TL;DR

This paper investigates the delay times of Type Ia supernovae in the core-degenerate scenario, emphasizing the role of magneto-dipole radiation in spinning down rapidly rotating white dwarfs to trigger explosions.

Contribution

It introduces a detailed analysis of spin-down timescales in the core-degenerate scenario, highlighting magneto-dipole radiation as a key mechanism for delay times.

Findings

Gravitational radiation is ineffective in spinning down white dwarfs.

Magneto-dipole radiation can produce delay times consistent with observed SNe Ia.

The delay from stellar formation to explosion is mainly determined by spin-down processes.

Abstract

We study the spinning down time scale of rapidly rotating white dwarfs (WDs) in the frame of the core-degenerate (CD) scenario for type Ia supernovae (SNe Ia). In the CD scenario the Chandrasekhar or super-Chandrasekhar mass WD is formed at the termination of the common envelope phase or during the planetary nebula phase, from a merger of a WD companion with the hot core of a massive asymptotic giant branch star. In the CD scenario the rapidly rotating WD is formed shortly after the stellar formation episode, and the delay from stellar formation to explosion is basically determined by the spin-down time of the rapidly rotating merger remnant. We find that gravitational radiation is inefficient in spinning down WDs, while the magneto-dipole radiation torque can lead to delay times that are required to explain SNe Ia.