Links between the shock instability in core-collapse supernovae and asymmetric accretions of envelopes

TL;DR

This paper investigates how asymmetric accretion flows and pre-shock perturbations influence shock revival in core-collapse supernovae, highlighting the importance of multi-dimensional effects and instabilities in the explosion mechanism.

Contribution

It provides a linear stability analysis showing that non-spherical, unsteady accretion flows can excite instabilities and aid shock revival, linking progenitor asymmetries to explosion outcomes.

Findings

Pre-shock perturbations efficiently excite fluid instabilities.

Asymmetric accretion flows facilitate shock revival.

Multi-dimensional effects are crucial for supernova explosions.

Abstract

The explosion mechanism of core-collapse supernovae has not been fully understood yet but multi-dimensional fluid instabilities such as standing accretion shock instability (SASI) and convection are now believed to be crucial for shock revival. Another multi-dimensional effect that has been recently argued is the asymmetric structures in progenitors, which are induced by violent convections in silicon/oxygen layers that occur before the onset of collapse, as revealed by recent numerical simulations of the last stage of massive star evolutions. Furthermore, it has been also demonstrated numerically that accretions of such non-spherical envelopes could facilitate shock revival. These two multi-dimensional may hence hold a key to successful explosions. In this paper, we performed a linear stability analysis of the standing accretion shock in core-collapse supernovae, taking into account non-spherical, unsteady accretion flows onto the shock to clarify the possible links between the two effects. We found that such pre-shock perturbations can excite the fluid instabilities efficiently and hence help the shock revive in core-collapse supernovae.