Empirical Relations for the Sensitivities of Solar-like Oscillations to Magnetic Perturbations

TL;DR

This paper derives empirical relations to estimate how magnetic fields perturb the oscillation frequencies of solar-like stars across different evolutionary stages, aiding interpretation of stellar oscillation data.

Contribution

It provides new polynomial-based relations for mode sensitivities that vary with stellar evolution, improving upon previous models.

Findings

Relations differ from previous literature

Sensitivity relations change across stellar evolution stages

Can assess magnetic perturbation effects on oscillation frequencies

Abstract

Oscillation mode frequencies of stars are typically treated as static for a given stellar model. However, in reality they can be perturbed by time varying sources such as magnetic fields and flows. We calculate the sensitivities of radial p-mode oscillations of a set of models for masses between 0.7-3.0 M$_{\odot}$ from the main sequence to the early asymptotic giant branch. We fit these mode sensitivities with polynomials in fundamental stellar parameters for six stages of stellar evolution. We find that the best-fitting relations differ from those proposed in the literature and change between stages of stellar evolution. Together with a measure of the strength of the perturbation, e.g., of the level of magnetic activity, the presented relations can be used for assessing whether a star's observed oscillation frequencies are likely to be close to the unperturbed ground state or whether they should be adjusted.