Imprint of the magnetic activity cycle on solar asteroseismic characterisation based on 26 years of GOLF and BiSON data

TL;DR

This study investigates how the Sun's magnetic activity cycle influences asteroseismic measurements over 26 years, revealing a significant impact on stellar age determination that could affect future stellar characterization efforts.

Contribution

It provides the first long-term analysis of magnetic activity's effect on solar asteroseismic parameters, highlighting the need to account for activity cycles in stellar models.

Findings

Magnetic activity cycle leaves a detectable imprint on solar age estimates.

Variations of up to 6.5% in age determination between activity minima and maxima.

Magnetic activity effects persist despite surface effect corrections.

Abstract

Building on the success of previous missions, asteroseismic modelling will play a key role in future space-based missions, such as PLATO, CubeSpec, and Roman. Despite remarkable achievements, asteroseismology has revealed significant discrepancies in the physics of theoretical stellar models, which have the potential to bias stellar characterisation at the precision level demanded by PLATO. The current modelling strategies largely overlook magnetic activity, assuming that its effects are masked by filtering the so-called surface effects. Given the presence of activity cycles in multiple solar-like oscillators, and activity variations in a significant fraction of Kepler observations of main-sequence stars (Santos et al. 2019b, 2021, 2023), we measured the impact of magnetic activity on the asteroseismic characterisation of the Sun based on 26.5 years of GOLF and BiSON observations. While magnetic activity is partially absorbed in the treatment of surface effects, we found a discernible imprint of the activity cycle in the determination of the solar age. Notably, this imprint persists across both BiSON and GOLF datasets, with significant variations of up to 6.5% observed between solar minima and maxima. Considering that the Sun exhibits low levels of activity, our study underscores the looming challenge posed by magnetic activity for future photometry missions, and prompts a potential reevaluation of the asteroseismic characterisation of Kepler's most active targets.