Search

We report that our optical spectroscopic observation of the young solar-type star EK Draconis reveals the first evidence for a stellar filament eruption associated with a superflare on a young Sun-like star EK Draconis. We monitored EK Draconis for about 30 nights with the TESS’s optical photometry and ground-based spectroscopy, and finally detected a superflare in white-light and Hα. After the superflare with the radiated energy of 2.0×1033 erg, a blue-shifted Hα absorption component with a large velocity of -510 km s-1 appeared. The temporal changes in the spectra greatly resemble the Sun-as-a-star spectra of solar filament eruptions, indicating a common picture of solar and stellar filament eruptions. The comparison of this stellar filament eruption with solar filament eruptions in terms of the length scale and velocity strongly suggests that this would eventually become a stellar CME. The mass of erupted filament of 1.1×1018 g is surprisingly 10 times larger than those of the largest solar CMEs. The huge filament eruption and a possible associated CME on the young Sun-like star provide the first opportunity to evaluate how the young Sun-like star/young Sun can affect the environment of young exoplanets/young Earth as well as stellar mass and angular-momentum evolution., {"references":["Maehara, H. et al. (2012), Nature, 485, 478","Namekata, K. et al. (2021), Nature Astronomy, 6, 241","Namekata, K. et al. (2022), ApJ Letters, 926, 5","Namekata, K. et al. (2022), ApJ, 933, 209","Vida, K. et al. (2016), A&A, 590, A11"]}