Solar cycle variations of large frequency separations of acoustic modes: Implications for asteroseismology

TL;DR

This study investigates how solar cycle variations affect large frequency separations of acoustic modes, which are crucial for stellar property estimation in asteroseismology, using BiSON data and multiple analysis methods.

Contribution

It introduces a comparative analysis of three methods for estimating large frequency separations and models solar cycle effects, highlighting their sensitivities and implications for asteroseismic studies.

Findings

Large frequency separations vary with the solar cycle.

Different estimation methods show offsets and sensitivities.

A simple model predicts cycle-induced variations in large separations.

Abstract

We have studied solar cycle changes in the large frequency separations that can be observed in Birmingham Solar Oscillations Network (BiSON) data. The large frequency separation is often one of the first outputs from asteroseismic studies because it can help constrain stellar properties like mass and radius. We have used three methods for estimating the large separations: use of individual p-mode frequencies, computation of the autocorrelation of frequency-power spectra, and computation of the power spectrum of the power spectrum. The values of the large separations obtained by the different methods are offset from each other and have differing sensitivities to the realization noise. A simple model was used to predict solar cycle variations in the large separations, indicating that the variations are due to the well-known solar cycle changes to mode frequency. However, this model is only valid over a restricted frequency range. We discuss the implications of these results for asteroseismology.