GYRE: An open-source stellar oscillation code based on a new Magnus Multiple Shooting Scheme

TL;DR

GYRE is a new open-source stellar oscillation code that employs a novel Magnus Multiple Shooting scheme, offering high accuracy, robustness, and efficiency for modeling stellar pulsations, and is validated against existing solutions.

Contribution

The paper introduces GYRE, a new stellar oscillation code using a Magnus Multiple Shooting scheme, improving accuracy and computational efficiency over traditional methods.

Findings

Code achieves up to 6th order accuracy.

Good agreement with analytic solutions and other codes.

Explores asteroseismic changes in a 1.5 M_sun star during evolution.

Abstract

We present a new oscillation code, GYRE, which solves the stellar pulsation equations (both adiabatic and non-adiabatic) using a novel Magnus Multiple Shooting numerical scheme devised to overcome certain weaknesses of the usual relaxation and shooting schemes appearing in the literature. The code is accurate (up to 6th order in the number of grid points), robust, efficiently makes use of multiple processor cores and/or nodes, and is freely available in source form for use and distribution. We verify the code against analytic solutions and results from other oscillation codes, in all cases finding good agreement. Then, we use the code to explore how the asteroseismic observables of a 1.5 M_sun star change as it evolves through the red-giant bump.