Flame Evolution During Type Ia Supernovae and the Deflagration Phase in the Gravitationally Confined Detonation Scenario

TL;DR

This paper introduces an improved method for tracking nuclear flames in Type Ia supernova simulations, focusing on the deflagration phase within the gravitationally confined detonation model, and explores how ignition location influences explosion outcomes.

Contribution

The authors develop a new, efficient flame tracking method that accurately models energy release and ash dynamics, reducing noise and resolution issues in supernova simulations.

Findings

The new method reduces acoustic noise in simulations.

Detonation density structure correlates with ignition point distance.

Ignition location variability may explain supernova brightness diversity.

Abstract

We develop an improved method for tracking the nuclear flame during the deflagration phase of a Type Ia supernova, and apply it to study the variation in outcomes expected from the gravitationally confined detonation (GCD) paradigm. A simplified 3-stage burning model and a non-static ash state are integrated with an artificially thickened advection-diffusion-reaction (ADR) flame front in order to provide an accurate but highly efficient representation of the energy release and electron capture in and after the unresolvable flame. We demonstrate that both our ADR and energy release methods do not generate significant acoustic noise, as has been a problem with previous ADR-based schemes. We proceed to model aspects of the deflagration, particularly the role of buoyancy of the hot ash, and find that our methods are reasonably well-behaved with respect to numerical resolution. We show that if a detonation occurs in material swept up by the material ejected by the first rising bubble but gravitationally confined to the white dwarf (WD) surface (the GCD paradigm), the density structure of the WD at detonation is systematically correlated with the distance of the deflagration ignition point from the center of the star. Coupled to a suitably stochastic ignition process, this correlation may provide a plausible explanation for the variety of nickel masses seen in Type Ia Supernovae.