The Sun, like other magnetically active stars, frequently ejects massive clouds of plasma and magnetic fields known as coronal mass ejections (CMEs). As CMEs travel through space, they create a sheath region—an area of compressed plasma and magnetic fields ahead of the CME. These sheaths can significantly impact planetary environments, posing space weather hazards to Earth and other planets. Mercury and Venus, being closer to the Sun and lacking Earth's protective magnetic field, experience more extreme effects from CMEs and their sheaths. These planets are natural laboratories for studying space weather on unmagnetized or weakly magnetized bodies. Using remote observations from various telescopes, an advanced model tool will be developed at the University of Helsinki to study the impact of sheath regions, helping to understand space weather effects on Mercury, Venus, and serve as a foundation for exploring the effects of space weather on exoplanetary systems and habitability.

2026

2029