Thermonuclear explosions of rapidly rotating white dwarfs

II. Detonations

J. M. M. Pfannes¹, J. C. Niemeyer^1,2 and W. Schmidt^1,2

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

Received: 10 March 2009
Accepted: 1 October 2009

Abstract

Context. Superluminous type Ia supernovae (SNe Ia) may be explained by super-Chandrasekhar-mass explosions of rapidly rotating white dwarfs (WDs). In a preceding paper, we showed that the deflagration scenario applied to rapidly rotating WDs generates explosions that cannot explain the majority of SNe Ia.

Aims. Rotation of the progenitor star allows super-Chandrasekhar mass WDs to form that have a shallower density stratification. We use simple estimates of the production of intermediate and iron group elements in pure detonations of rapidly rotating WDs to assess their viability in explaining rare SNe Ia.

Methods. We numerically construct WDs in hydrostatic equilibrium that rotate according to a variety of rotation laws. The explosion products are estimated by considering the density stratification and by evaluating the result of hydrodynamics simulations.

Results. We show that a significant amount of intermediate mass elements is produced for theoretically motivated rotation laws, even for prompt detonations of WDs.

Conclusions. Rapidly rotating WDs that detonate may provide an explanation of rare superluminous SNe Ia in terms of both burning species and explosion kinematics.