ASTRONUM 2023 Poster

I presented this poster at the ASTRONUM 2023 Meeting in Pasadena. My poster is on modeling the Convective Urca process in simmering white dwarfs using the low mach code MAESTROeX.

Abstract

Low Mach Number Simulations of the Convective Urca Process

A proposed setting for thermonuclear (Type Ia) supernovae is a white dwarf that has gained mass from a companion to the point of carbon ignition in the core. There is a simmering phase in the early stages of burning that involves the formation and growth of a core convection zone. One aspect of this phase is the convective Urca process, a linking of weak nuclear reactions to convection which may alter the composition and structure of the white dwarf. Convective Urca is not well understood and requires 3D fluid simulations to realistically model. Additionally, the convection is relatively slow (Mach number less than 0.005) so a low-Mach method is needed. Using the MAESTROeX low-Mach hydrodynamic software, we present full 3D simulations of the A=23 convective Urca process. These results point to the proper initial conditions needed for the simulation to quickly settle into a quasi-steady state. Our findings on the extent of mixing across the Urca shell, the characteristic velocities of the flow and the energy loss rates can be used to inform 1D stellar models which track the longer-timescale evolution.

This research was supported in part by the US Department of Energy (DOE) under grant DE-FG02-87ER40317

The full poster can be downloaded here.