Three-dimensional Structure of Incomplete Carbon-Oxygen Detonations in Type Ia Supernovae

TL;DR

This study uses multidimensional simulations to explore the structure, stability, and propagation of incomplete carbon-oxygen detonations in Type Ia supernovae, revealing significant differences from lower-dimensional models and implications for observed light-curve features.

Contribution

It provides the first detailed three-dimensional analysis of CO detonations, highlighting their enhanced robustness and the influence of initial conditions on their cellular structure and burning process.

Findings

3D CO detonations are more stable and propagate more reliably than 1D and 2D models.

Detonation cell size depends on background density and initial composition.

Implications for early light-curve bumps in Type Ia supernovae.

Abstract

Carbon-oxygen (CO) detonation with reactions terminating either after burning of C$^{12}$ in the leading C$^{12}$ + C$^{12}$ reaction or after burning of C$^{12}$ and O$^{16}$ to Si-group elements may occur in the low-density outer layers of exploding white dwarfs and be responsible for the production of intermediate-mass elements observed in the outer layers of Type Ia supernovae. Basic one-dimensional properties of CO-detonations have been summarized in our previous work. This paper presents the results of two- and three-dimensional numerical simulations of low-density CO-detonations and discusses their multidimensional stability, cellular structure, and propagation through a constant low-density background. We find three-dimensional CO detonations to be strikingly different from their one-dimensional and two-dimensional counterparts. Three-dimensional detonations are significantly more robust and capable of propagating without decay compared to highly unstable and marginal one- and two- dimensional detonations. The detonation cell size and whether burning of C$^{12}$ in a three-dimensional detonation wave is followed by the subsequent O$^{16}$ burning is sensitive to both the background density and the initial C$^{12}$ to O$^{16}$ mass ratio. We also discuss the possible implications for understanding the observed early time bumps in light-curves.