Imprint of the magnetic activity cycle on the asteroseismic characterisation of the Sun

Asteroseismic modelling will play a key role in future space-based missions, such as PLATO, CubeSpec, and Roman. Depite 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 within the parametrisation of 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. 2019, 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 (Bétrisey et al. 2024). 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. This imprint persists across both BiSON and GOLF datasets, with significant variations of up to 6.5% observed between solar minima and maxima. As 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 the most active Kepler targets.