[A-OS11] 陸域海洋相互作用-惑星スケール物質循環

[AOS11-09] Radiological Assessment of Martian and Terrestrial Surface during Young Sun

*山敷 庸亮¹、前原 裕之⁶、野津 湧太³、佐藤 達彦²、アイラペディアン ウラジミール⁷、野津 翔太³、黒木 龍介¹、村嶋 慶哉⁵、佐藤 啓明⁴、坂東 日菜⁵、行方 宏介³、佐々木 貴教³、スコット トーマス⁸、野上 大作³、柴田 一成⁹ (1.京都大学大学院総合生存学館、2.日本原子力機構、3.京都大学大学院理学研究科、4.京都大学工学部、5.京都大学理学部、6.国立天文台、7.NASAゴダード宇宙飛行センター、8.ブリストル大学、9.京都大学理学部附属花山天文台)

キーワード：若い太陽、太陽フレア、放射線環境

For a terrestrial planetary system, during the initiation period of planetary formation, the activity of a young Sun is extremely important in order to comprehend the atmospheric behavior of the planet. Relatively lower luminosity associated with lower surface temperature of the young Sun brings the planets a cooler surface environment. Terrestrial and Martian surfaces become icy cold in this environment without considering extensive GHG formation. Within such environments, the dose from SEP from a young Sun might play an important role in primordial atmospheric composition.


Here, we propose a reasonable radiological assssessment of the possible exposure intensity in SEP from a young Sun, by evaluating the possible magnitude and frequency of early solar flares by using possible star spot area, derived from their rotational period. We evaluated annual and maximum flare energy in different cases of solar spot areas for 3 %, 5 % ,and 10 % of solar surfaces. The maximum dose at the Martian TOA reaches 5.86 k Gy (265 Sv) when the solar spot area reaches 10 % of the solar surface. Such higher radiation dose may have influenced significantly atmospheric composition of Early Mars and Young Earth.