[P-EM11] Frontiers in solar physics

[PEM11-10] Rapid, short-duration prominence eruptions in M-dwarf: Insights from solar observations

*Yuto Kajikiya¹, Kosuke Namekata², Yuta Notsu³, Kai Ikuta⁴, Hiroyuki Maehara⁵, Daisaku Nogami², Bunei Sato¹ (1.Institute of Science Tokyo, 2.Kyoto University, 3.University of Colorado Boulder, 4.University of Tokyo, 5.National Astronomical Observatory of Japan)

Keywords:Stellar flares, Stellar coronal mass ejections, M dwarf stars

Flares are sudden explosive events occurring in the corona of the Sun and other stars. On the Sun, flares are often accompanied by coronal mass ejections (CMEs), impacting planetary atmospheres and magnetospheres. Recently, the discovery of multiple habitable planets around M-dwarfs has drawn attention to M-dwarf flares/CMEs and their impacts on planets. Previous spectroscopic observations of M-dwarf flares often show blue/red asymmetries in the Hα line profiles, suggesting prominence eruptions (early CME stages). Many of these events show velocities around 100 km/s, slower than typical solar prominence eruptions, and durations exceeding 20 minutes. However, previous studies, with time cadence of over 5 minutes, might have missed rapid plasma velocity changes due to the strong surface gravity of M-dwarfs, potentially missing short-duration prominence eruptions (e.g., Notsu et al. 2024). In this study, we conducted spectroscopic observations of the active M-dwarf YZ CMi, with an unprecedented high time cadence of approximately 1 minute using the Seimei telescope, simultaneously with high-precision photometric observations by TESS. As a result, we detected 27 Hα flares, among which 5 show red asymmetries and 3 show blue asymmetries in the Hα line profile. Particularly, two events (one blue asymmetry event and one red asymmetry event) suggest rapid, short-duration prominence eruptions with durations of approximately 5 minutes and velocities exceeding 300 km/s (Kajikiya et al. 2025). Our discovery of short-duration events suggests that previous studies with low time cadence may have missed these events, potentially leading to an underestimation of the occurrence frequency of prominence eruptions/CMEs on M-dwarfs. These results provide significant insights into CMEs that can affect planetary habitability around M-dwarfs.