A Solar cycle correlation of coronal element abundances in Sun-as-a-star observations

TL;DR

This study demonstrates that the elemental composition of the Sun's corona varies cyclically with solar activity, as observed through full-disk data, highlighting the importance of long-term observations for understanding stellar coronae.

Contribution

It shows a clear correlation between coronal composition and solar cycle phase using Sun-as-a-star observations, emphasizing the role of magnetic activity in elemental abundance variations.

Findings

Coronal composition varies with the solar cycle.

Spectroscopic cyclic variations are detectable in X-ray observations.

Coronal magnetic activity influences plasma composition.

Abstract

The elemental composition in the coronae of low-activity solar-like stars appears to be related to fundamental stellar properties such as rotation, surface gravity, and spectral type. Here we use full-Sun observations from the Solar Dynamics Observatory, to show that when the Sun is observed as a star, the variation of coronal composition is highly correlated with a proxy for solar activity, the F10.7 cm radio flux, and therefore with the solar cycle phase. Similar cyclic variations should therefore be detectable spectroscopically in X-ray observations of solar analogs. The plasma composition in full-disk observations of the Sun is related to the evolution of coronal magnetic field activity. Our observations therefore introduce an uncertainty into the nature of any relationship between coronal composition and fixed stellar properties. The results highlight the importance of systematic full-cycle observations for understanding the elemental composition of solar-like stellar coronae.