Turbulence in Wind-Blown Bubbles around Massive Stars

TL;DR

This study uses two-dimensional hydrodynamic simulations to analyze turbulence development in wind-blown bubbles around massive stars, revealing vortex formation and Rayleigh-Taylor instabilities that influence supernova shock evolution.

Contribution

It provides new insights into turbulence onset and growth in stellar wind bubbles through detailed simulations, including implications for supernova dynamics.

Findings

Vortex rolls form during the Main-Sequence stage.

Rayleigh-Taylor instabilities occur in later stages.

Significant non-radial kinetic energy develops before star death.

Abstract

Winds from massive stars (> 8 solar masses) result in the formation of wind-blown "bubbles" around these stars. In this paper we study, via two-dimensional numerical hydrodynamic simulations, the onset and growth of turbulence during the formation and evolution of these wind-blown "bubbles". Our simulations reveal the formation of vortex rolls during the Main-Sequence stage of the evolution, and Rayleigh-Taylor instabilities in the subsequent stages due to accelerating and/or decelerating wind-blown shells. The bubble shows a very turbulent interior just prior to the death of the star, with a significant percentage of the internal energy expended in non-radial motions. This would affect the subsequent evolution of the resultant supernova shock wave. We discuss the implications of these results, show how the ratio of kinetic energy in radial versus non-radial motions varies throughout the evolution, and discuss how these results would carry over to three dimensions.