The Antesonic Condition: Understanding the Critical Explosion Criterion

Abstract

In the model problem of steady spherically-symmetric pressure-less free-fall onto a standing shockwave around an accreting central mass, the “antesonic” condition limits the regime of stable accretion to $c^2_T/v^2_{\rm esc}\leq 3/16$, where $c_T$ is the isothermal sound speed in the subsonic post-shock flow, and $v_{\rm esc}$ is the escape velocity at the shock radius. Above this limit, it is impossible to simultaneously satisfy the time-steady Euler equation and the strong shock-jump conditions, and the system undergoes a time-dependent transition to a thermal wind. This physics has been shown to explain the existence of a critical neutrino luminosity in steady-state models of proto-neutron star accretion in the context of core-collapse supernovae. We extend the antesonic condition to flows with rotation and turbulence using a simple one-dimensional formalism that highlights the basic physics of the antesonic condition and its generalizations to more complicated flows. The analysis suggests a framework to better understand its applicability to 3D simulations.

Date
Sep 26, 2019 11:45 AM — 12:00 PM
Location
The Ohio State University: Center for Cosmology and AstroParticle Physics
Matthias J. Raives
CTAC Fellow

I use analytic and computational methods to study the supernova explosion mechanism and the magnetocentrifugal winds of newly born neutron stars.