Thermonuclear explosions of rapidly rotating white dwarfs - I. Deflagrations

TL;DR

This study investigates how rapid rotation in white dwarf stars affects turbulent deflagrations, revealing that rotation causes anisotropic flames and leaves unburned matter, challenging the viability of this model for Type Ia supernovae.

Contribution

It is the first detailed 3D hydrodynamical simulation analysis of rapidly rotating white dwarfs in the deflagration scenario for Type Ia supernovae.

Findings

Rotation causes flame anisotropy towards the poles.

Significant unburned matter remains along the equator.

Rapid rotation is incompatible with observed SNe Ia spectral features.

Abstract

Context: Turbulent deflagrations of Chandrasekhar mass White Dwarfs are commonly used to model Type Ia Supernova explosions. In this context, rapid rotation of the progenitor star is plausible but has so far been neglected. Aims: The aim of this work is to explore the influence of rapid rotation on the deflagration scenario. Methods: We use three dimensional hydrodynamical simulations to model turbulent deflagrations ignited within a variety of rapidly rotating CO WDs obeying rotation laws suggested by accretion studies. Results: We find that rotation has a significant impact on the explosion. The flame develops a strong anisotropy with a preferred direction towards the stellar poles, leaving great amounts of unburnt matter along the equatorial plane. Conclusions: The large amount of unburnt matter is contrary to observed spectral features of SNe Ia. Thus, rapid rotation of the progenitor star and the deflagration scenario are incompatible in order to explain SNe Ia.