Radial Stellar Pulsation and Three-Dimensional Convection. II. Two-Dimensional Convection In Full Amplitude Radial Pulsation

TL;DR

This paper introduces a new 2D radiation hydrodynamics code that simulates the full amplitude interaction of convection and radial pulsation in variable stars, improving the match with observed light curves.

Contribution

The authors developed a novel 2D simulation method that maintains constant mass in spherical shells, enabling full amplitude pulsation modeling and better reproducing observed star light curves.

Findings

2D simulations match observed light curves better near the red edge of RR Lyrae stars.

The new code successfully reaches full pulsation amplitude without radial drift issues.

Improved modeling of convection-pulsation interaction enhances understanding of variable star behavior.

Abstract

We have developed a three-dimensional radiation hydrodynamics code to simulate the interaction of convection and radial pulsation in classical variable stars. One key goal is the ability to carry these simulations to full amplitude in order to compare them with observed light curves. Previous multi-dimensional calculations were prevented from reaching full amplitude because of drift in the radial coordinate system, due to the algorithm defining radial movement of the coordinate system during the pulsation cycle. We have removed this difficulty by defining our radial coordinate flow algorithm to require that the mass in a spherical shell remains constant for every time-step throughout the pulsation cycle. We have used our new code to perform 2D simulations of the interaction of radial pulsation and convection. We have made comparisons between light curves from our 2D convective simulations with observed light curves and find that our 2D simulated light curves are better able to match the observed light curve shape near the red edge of the RR Lyrae instability strip than light curves from previous 1D time dependent convective models.