LASP Science Seminars

Abstract: Young Sun-like stars frequently produce “superflares”, serving as models for the young Sun-Earth environment. Large solar flares are closely linked to coronal mass ejections (CMEs) associated with filament/prominence eruptions, but its evidence for stellar superflares remains scarce. Since fast and massive CMEs and strong XUV radiation from superflares can significantly change the chemistry and escaping ratio of planetary atmosphere, the CME association should be investigated to understand the habitable worlds on the early Venus, Earth and Mars and young exoplanets. In this talk, I present the result of 5-year large campaign observations of young Sun-like stars (25-100 Myr age), with Japanese ground-based telescopes and NASA’s TESS & NICER mission. We discovered the first evidence of gigantic prominence eruptions associated with superflares that have velocities of 400-700 km/s and masses of 10^17-20 g, as a strong evidence that CMEs can affect the young planetary systems. Our research suggests a high frequency of massive CME occurrences, which indicates that high-energy particles frequently interact with young planetary atmospheres and can produce sufficient prebiotic compounds and amino acids. To further investigate CME propagation, we have performed campaign observations using the Hubble Space Telescope in collaboration with LASP researchers. In this talk, I will present these findings and also introduce the science to be conducted in future missions such as Japan’s LAPYUTA mission and the US’s ESCAPE mission.