[A-OS11] Continental-Oceanic Mutual Interaction: Planetary scale Material Circulation

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

*Yosuke Alexandre Yamashiki¹, Hiroyuki Maehara⁶, Yuta Notsu³, Tatsuhiko Sato², Airapetian Vladimir⁷, Shota Notsu³, Ryusuke Kuroki¹, keiya murashima⁵, Hiroaki Sato⁴, Hina Bando⁵, Kosuke Namekata³, Takanori Sasaki³, Scott Thomas⁸, Nogami Daisaku³, Kazunari Shibata⁹ (1.Earth & Planetary Water Resources Assessment Laboratory Graduate School of Advanced Integrated Studies in Human Survivability Kyoto University, 2.Japan Atomic Energy Agency, 3.Graduate School of Science, Kyoto University, 4.School of Engineering, 5.School of Science, 6.National Astronomical Observatory of Japan, 7.NASA / Goddard Space Flight Center, 8.University of Bristol , 9.Kwasan Astronomical Observatory, Kyoto University)

Keywords:Young Sun, Solar Flare, Radiological Condition

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.