35 - The interplay between nuclear electron capture and fluid dynamics in core collapse supernovae

Summary

Abstract

As we investigate the manifestly multi-dimensional nature of core collapse supernovae, the connection between microscopic physics and macroscopic fluid motion must not be forgotten. As an example, we discuss nuclear electron capture and its impact on the supernova shock. Though electron capture on nuclei with masses larger than 60 is the most important nuclear interaction to the dynamics of stellar core collapse, in prior simulations of core collapse it has been treated in a highly parameterized fashion, if not ignored. With a realistic treatment of electron capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as their ramifications for the post-bounce evolution in core collapse supernovae.

Introduction

The many observations of asymmetries in core collapse supernovae, coupled with the failure of spherically symmetric simulations of the neutrino reheating paradigm to produce explosions, has persuaded the community that multidimensional effects like convection and other fluid instabilities must be vital elements of the supernova mechanism (Wilson & Mayle 1993, Herant et al. 1994, Burrows et al. 1995, Fryer & Warren 2002) though, even with these convective enhancements, explosions are not guaranteed (Janka & Müller 1996, Mezzacappa et al. 1998, Buras et al. 2003). This view has been reinforced in recent years by the failure of more accurate spherically symmetric multigroup Boltzmann simulations to produce explosions (Rampp & Janka 2000, Mezzacappa et al. 2001, Liebendörfer et al. 2001, Thompson et al. 2003).