Thermonuclear explosions of rapidly rotating white dwarfs

I. Deflagrations

¹ Lehrstuhl für Astronomie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany e-mail: pfannes@astro.uni-wuerzburg.de
² Institut für Astrophysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany e-mail: [niemeyer;schmidt]@astro.physik.uni-goettingen.de
³ Institut für Angewandte Mathematik, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany e-mail: klingenberg@mathematik.uni-wuerzburg.de

Received: 10 March 2009
Accepted: 27 October 2009

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.