[P-AE16] 系外惑星

[PAE16-04] 太陽系外惑星におけるフレア影響の体系化

*山敷 庸亮¹、前原 裕之²、Airapetian Vladimir³、野津 湧太⁶、行方 宏介⁴、清水 里香⁵、木村 なみ¹、佐藤 達彦⁷、佐々木 貴教⁴ (1.京都大学大学院総合生存学館、2.国立天文台岡山分室、3.NASA/GSFC、4.京都大学理学研究科、5.京都大学理学部、6.コロラド大学ボルダー校、7.原子力研究開発機構)

キーワード：太陽系外惑星、恒星高エネルギー粒子、ホスト星

The Search for Extra-terrestrial Mother Planets Catalogue will be used to search for potentially habitable mother planets and to derive data on stellar activity of their host stars. The ultimate goal of the survey is to accomplish creating a full and original data catalogue of exoplanets at Kyoto University, based on the Exokyoto catalogue, while paying special attention to characterization of stellar activity of planet hosts. We presented the first quantitative impact evaluation system of stellar flares on the habitability factors with an emphasis on the impact of stellar proton events. We derive the maximum flare energy from stellar star spot sizes and examine the impacts of flare-associated ionizing radiation on CO₂, H₂, and N₂+ O₂-rich atmospheres of a number of well-characterized terrestrial type exoplanets. Our simulations based on the Particle and Heavy Ion Transport code System suggest that the estimated ground-level dose for each planet in the case of terrestrial-level atmospheric pressure (1 bar) for each exoplanet does not exceed the critical dose for complex (multicellular) life to persist, even for the planetary surface of Proxima Centauri b, Ross-128 b, and TRAPPIST-1 e. We re-conduct numerical simulation based on newely obtained spectra for the possible CME occurred in those planetary system, revailing higher and harder spectra may induce significant damage even for those "habitable"planets. Some thick atmosphere and hydrosphere may protect their habitability reducing exposure impact for those planet. Together with the observation for H-alpha for host stars we also are attempt to conduct developing database for those risk for potentially habitable planetary system.
In this presentation we will introduce how the energy spectra of potential CME may affect entire estimation of the possible dose at the surface environment of extrasolar planets with preliminary classification by stellar impact among "habitable" planets situated CHZ based on the conventional classification theory. According to our estimation, some planets with hardest energy spectra and higher atmospheric escape rate the surface environment become severe for terrestrial-type life system.