09/13/2023
By Lynne Schaufenbil
Abstract
Solar flares are often accompanied by filament/prominence eruptions, sometimes leading to coronal mass ejections (CMEs). By analogy, we expect that stellar flares are also associated with stellar CMEs whose properties are essential to know the impact on exoplanet habitability. Probable detections of stellar CMEs are still rare, but in very recent years, there have been several reports that stellar (super-)flares on G,K,M dwarfs show blue-shifted optical/UV/X-ray emissions lines, XUV/FUV dimming, and radio bursts. Some of them are interpreted as indirect evidence of stellar prominence eruptions/CMEs on cool stars. In particular, we have worked on the observation campaigns of young G-dwarfs (solar-type stars) and M-dwarfs and have reported evidence of stellar filament/prominence eruptions, probably leading to a CME, as a blue-shifted absorption of chromospheric lines associated with a superflare. Notably, the erupted masses for superflares are larger than those of the largest solar CMEs, indicating severe influence on exoplanet environments. These mass is roughly consistent with the scaling relation expected from solar CMEs. However, the ratio of the kinetic energy of stellar CMEs to flare energy is significantly smaller than expected from the solar scaling relation and this discrepancy is still in debate. In this talk, we will introduce recent updates of stellar CME studies especially focusing on our recent reports of stellar filament/prominece eruptions, and discuss the future prospects including the importance of more collaborations with solar-based observation/modeling studies.
Short bio
Yuta Notsu got his Ph.D. in March 2019 at Kyoto University in Japan. After that, he worked as a postdoc at Laboratories for Atmospheric and Space Physics, University of Colorado Boulder. He is studying stellar magnetic activities especially "superflares" on solar-type (G-type) stars and cooler K,M-type stars, using the various photometric and spectroscopic data from space and ground telescopes.
If you are interested in attending, please contact Lynne_Schaufenbil@uml.edu for the Zoom link.