A devil in the detail: parameter cross-talk from the solar cycle and estimation of solar p-mode frequencies

TL;DR

This paper investigates how the solar activity cycle causes subtle cross-talk effects in the measurement of solar p-mode frequencies, potentially biasing solar structure inferences from long-term observations.

Contribution

It identifies and analyzes a cross-talk effect caused by simultaneous variations in solar p-mode parameters, highlighting its impact on frequency estimation and solar structure studies.

Findings

Cross-talk effect biases p-mode frequency estimates.

Effect causes small distortions in power spectra.

Significance of the effect is marginal for Sun-as-a-star data.

Abstract

Frequencies, powers and damping rates of the solar p modes are all observed to vary over the 11-yr solar activity cycle. Here, we show that simultaneous variations of these parameters give rise to a subtle cross-talk effect, which we call the ``devil in the detail'', that biases p-mode frequencies estimated from analysis of long power frequency spectra. We also show that the resonant peaks observed in the power frequency spectra show small distortions due to the effect. Most of our paper is devoted to a study of the effect for Sun-as-a-star observations of the low-l p modes. We show that for these data the significance of the effect is marginal. We also touch briefly on the likely l dependence of the effect, and discuss the implications of these results for solar structure inversions.