Kosuke Namekata (National Astronomical Observatory of Japan, e-mail: kosuke.namekata@astro.nao.ac.jp)1 Hiroyuki Maehara1; Satoshi Honda2, Yuta Notsu3; Daisaku Nogami4; Kazunari Shibata4, and SMART & OISTER team collaborations (1) National Astronomical Observatory of Japan (NAOJ); (2) University of Hyogo; (3) Colorado University; (4) Kyoto University A Filament Erup/on and Coronal Mass Ejec/on from a Superﬂare on a Young Sun-like Star We report that our op*cal spectroscopic observa*on of the young solar-type star EK Draconis reveals the ﬁrst evidence for a stellar ﬁlament erupCon associated with a superﬂare on a young Sun-like star EK Draconis (Namekata et al. 2021 (or 2022), Nature Astronomy, 6, 241). We monitored EK Draconis for about 30 nights with the TESS’s op*cal photometry and ground-based spectroscopy, and ﬁnally detected a superﬂare in white-light and Hα. APer the superﬂare with radiated energy of 2.0x1033 erg, a blue-shiPed Hα absorp*on 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 erup*ons, indica*ng a common picture of solar and stellar ﬁlament erup*ons. The comparison of this stellar ﬁlament erup*on with solar ﬁlament erup*ons in terms of the length scale and velocity strongly suggests that this would eventually become a stellar CME. The mass of erupted ﬁlament of 1.1x1018 g is surprisingly 10 *mes larger than those of the largest solar CMEs. The huge ﬁlament erup*on and an associated CME on the young Sun-like star provide the ﬁrst opportunity to evaluate how the young Sun-like star/young Sun aﬀects the environment of young exoplanets/young Earth as well as stellar mass/angular-momentum evoluCon (cf. the faint young Sun paradox). 1. Introduc,on 3. Filament erup,on on young Sun-like star 2. Observa,ons 4. Sun-as-a-star analysis 5. Frequency of CMEs 7. References 6. Summary & Future Works 1. Namekata et al. 2021 online (or 2022a), Nature Astronomy, 6, 241(→) 2. Namekata et al. 2022b, ApJ Le?ers, 926,5 3. Namekata et al. 2022c, accepted (h?ps://arxiv.org/abs/2206.01395) [See, my talk in Splinter session “Solar and stellar coronal mass ejecOons” ] FIGURE 3: A solar ﬂare WITH ﬁlament erupOon. (middle) Light curve. (right) Dynamic spectrum of the Hα line (Namekata et al. 2021 (or 2022a), Nat. Astron.). What does the erup5ve event on EK Dra look like? To answer this quesOon, we conducted the Sun-as-as-star analysis of Hα spectrum of solar ﬁlament erupOons. As a results, spectral features are very similar to the event on EK Dra, indicaOng that the event on EK Dra was a large-scale ﬁlament erup5on whose picture is similar to those of solar ﬁlament erup5ons. Solar image Hα – 1Å ﬁlament ﬂare FIGURE 4: A solar flare WITHOUT a signature of filament eruption. In this case, strong redshifted & broadened spectrum can be seen (Namekata et al. 2022c, ApJ). ﬂare Velocity [km/s] Wavelength [Å] Impulsive Phase (ﬂare) Normalized Intensity Decay phase FIGURE 1: A stellar ﬁlament erupOon from a 2x1033 erg superﬂare on a young Sun- like star EK Dra. (le`) Light curve in Hα. (middle) pre-ﬂare subtracted spectrum (right) Dynamic spectrum (Namekata et al. 2021 (or 2022a), Nat. Astron.). We detected Hα spectra from superflares (1033-34 erg) on a young Sun-like stars for the first time. Surprisingly, one of them shows post-flare Hα dimming, and the Hα spectrum shows blue-shifted absorption component. We concluded that we detected a stellar filament eruption on young Sun-like star for the first time. FIGURE 2: Large velocity and length scale indicate that the ﬁlament erup5on eventually becomes stellar CMEs. ProperOes Velocity: -510 km/s Length scale: 500 Mm Mass: 1.1x1018 g (10 x the largest solar CME) Superﬂare FIGURE 5: NO ﬁlament erup5on signature in a 1034 erg superﬂare on a young Sun- like star EK Dra. (Namekata et al. 2022b, ApJ Le?ers). Other superﬂares DO NOT necessarily show ﬁlament erup5on signatures ⇒Signatures of ﬁlament erupOon