Simulating the outer layers of rapidly rotating stars

TL;DR

This study uses radiative hydrodynamic simulations to explore how rapid rotation affects convection and turbulence in the outer layers of stars, revealing that rotation suppresses turbulence and influences flow patterns.

Contribution

It provides the first detailed RHD simulations of convection in rapidly rotating stars with realistic physics, highlighting the interplay between rotation, radiative cooling, and flow dynamics.

Findings

Rotation reduces turbulence strength in stellar surface layers.

Radiative cooling creates a zonal velocity profile independent of rotation near the surface.

Deeper layer flows are primarily controlled by rotation.

Abstract

This paper presents the results of a set of radiative hydrodynamic (RHD) simulations of convection in the near-surface regions of a rapidly rotating star. The simulations use microphysics consistent with stellar models, and include the effects of realistic convection and radiative transfer. We find that the overall effect of rotation is to reduce the strength of turbulence. The combination of rotation and radiative cooling creates a zonal velocity profile in which the motion of fluid parcels near the surface is independent of rotation. Their motion is controlled by the strong up and down flows generated by radiative cooling. The fluid parcels in the deeper layers, on the other hand, are controlled by rotation.