Institut für Astronomie & Astrophysik

Eruptive Events in Active Stars: Lessons from Numerical Simulations

Julian Alvarado-Gomez, AIP — 08.02.2021

Flares and coronal mass ejections (CMEs) are more energetic than any other class of solar phenomena. These events involve the rapid release of up to 10^33 erg of magnetic energy in the form of particle acceleration, heating, radiation, and bulk plasma motion. Displaying much larger energies, their stellar counterparts are expected to play a fundamental role in shaping the evolution of activity and rotation, as well as the environmental conditions around low-mass stars. While flares are now routinely detected in multi-wavelength observations across all spectral types and ages, direct evidence for stellar CMEs is almost non-existent. In this context, numerical simulations provide a valuable pathway to shed some light on the eruptive behavior in the stellar regime. In this talk, I will review recent results obtained from realistic modeling of CMEs in active stars. Emphasis will be given to M dwarfs, focusing on possible observable coronal signatures of these events using next-generation X-ray missions. Furthermore, an explanation for the lack of Type II radio bursts from CMEs in active M dwarfs despite their frequent flaring will be discussed. Finally, the implications and relevance of these numerical results will be considered in the context of future characterization of host star-exoplanet systems.