Solar energetic events, the solar-stellar connection, and statistics of extreme space weather

TL;DR

This paper compares solar and stellar magnetic activity to understand extreme space weather, highlighting statistical properties and the challenges in interpreting energetic events from observations of the Sun and Sun-like stars.

Contribution

It provides a comparative analysis of solar and stellar activity statistics, revealing insights and gaps in understanding extreme space weather events.

Findings

Correlations between solar and stellar magnetic activity.

Challenges in interpreting stellar energetic events.

Insights into the frequency and intensity of extreme space weather.

Abstract

Observations of the Sun and of Sun-like stars provide access to different aspects of stellar magnetic activity that, when combined, help us piece together a more comprehensive picture than can be achieved from only the solar or the stellar perspective. Where the Sun provides us with decent spatial resolution of, e.g., magnetic bipoles and the overlying dynamic, hot atmosphere, the ensemble of stars enables us to see rare events on at least some occasions. Where the Sun shows us how flux emergence, dispersal, and disappearance occur in the complex mix of polarities on the surface, only stellar observations can show us the activity of the ancient or future Sun. In this review, I focus on a comparison of statistical properties, from bipolar-region emergence to flare energies, and from heliospheric events to solar energetic particle impacts on Earth. In doing so, I point out some intriguing correspondences as well as areas where our knowledge falls short of reaching unambiguous conclusions on, for example, the most extreme space-weather events that we can expect from the present-day Sun. The difficulties of interpreting stellar coronal light curves in terms of energetic events are illustrated with some examples provided by the SDO, STEREO, and GOES spacecraft.