AAS 241 Poster

I presented this poster at the 245th Winter AAS meeting. My poster is on modeling the Urca process in simmering white dwarfs using the low mach code MAESTROeX. Below you can find my abstract as well as a link to the virtual poster (called an iPoster).

Abstract

Simulations of Convective Urca Process in Type Ia SN Progenitor

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. Energy released during the early simmering phase of this carbon burning drives the formation and growth of a core convection zone. This convective period behaves very differently from that of long-lived stars; the star’s thermal timescales are relatively long compared to the short ~1000 year simmering phase. An additional complicating factor is the convective Urca process, a linking of weak nuclear reactions to convection that alters the composition and provides local cooling near a region dubbed the Urca shell. We explore this poorly understood process with full 3D reactive flow simulations with the low Mach number hydrodynamic code MAESTROeX for the A=23 Urca pair. MAESTROeX can simulate hundreds of convective turnovers during the simmering phase, allowing us to characterize the extent of mixing across the Urca shell and the structure of the convective boundary, and to calculate characteristic velocities of the flow and energy loss rates due to neutrino emission. Our results allow refinement of precursor models and can be used to inform 1D stellar models that track the longer-timescale evolution of the simmering phase.

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

The full poster can be seen here.