On the Road to Understanding Type Ia Progenitors: Precision Simulations of Double Degenerate Mergers

TL;DR

This paper reviews the state of double degenerate merger simulations for type Ia supernova progenitors, emphasizing the need for precision to determine whether systems undergo thermonuclear explosions or collapse.

Contribution

It highlights the discrepancies in current simulation results and proposes an approach using verification and validation to improve accuracy in predicting merger outcomes.

Findings

Current simulations show large differences in mass-transfer rates.

Precision simulations are necessary to determine merger fate.

Understanding lower-mass systems may aid in testing models.

Abstract

We review the current state of the art in double degenerate merger simulations to better understand the role this phenomenon plays in type Ia progenitors. Because the fate of a merged system may well depend on the exact evolution of the matter temperature (as well as mixing of the merged system), precision simulations are required to determine the true fate of these systems. Unfortunately, if we compare the results of current simulations, we find many-order of magnitude differences in quantities like mass-transfer rates in the merger process. We discuss these differences and outline an approach using verification and validation that should allow us to achieve a level of precision sufficient to determine the true fate (thermonuclear vs. collapse) of double degenerate mergers. Understanding the fate of lower-mass systems (e.g. R Coronae Borealis stars) may be key in our final testing phase.