2021/12/09 by Kosuke Namekata, Hiroyuki Maehara, Satoshi Honda +20
Physics and Astronomy · #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.1038/s41550-021-01532-8
40 pages, 4 figures, 4 extended data figures, published in Nature Astronomy (2021)
arxiv created 2021/12/09 · arxiv updated 2021/12/10
Solar flares are often accompanied by filament/prominence eruptions (∼104 K and ∼ 1010-11 cm-3), sometimes leading to coronal mass ejections (CMEs) that directly affect the Earth's environment. `Superflares' are found on some active solar-type (G-type main-sequence) stars, but the association of filament eruptions/CMEs has not been established. Here we show that our optical spectroscopic observation of the young solar-type star EK Draconis reveals the evidence for a stellar filament eruption associated with a superflare. This superflare emitted a radiated energy of 2.0×1033 erg, and blue-shifted hydrogen absorption component with a large velocity of -510 km s-1 was observed shortly after. The temporal changes in the spectra greatly resemble those of solar filament eruptions. Comparing this eruption with solar filament eruptions in terms of the length scale and velocity strongly suggests that a stellar CME occurred. The erupted filament mass of 1.1×1018 g is 10 times larger than those of the largest solar CMEs. The massive filament eruption and an associated CME provide the opportunity to evaluate how they affect the environment of young exoplanets/young Earth and stellar mass/angular-momentum evolution.