[P-PS01] Outer Solar System Exploration Today, and Tomorrow

[PPS01-03] Titan Seismology with DraGMetSEIS

*川村 太一¹、白石 浩章²、田中 智²、三谷 烈史²、小野寺 圭祐³、村上 英記⁴、山田 竜平⁷、鎌田 俊一⁸、木村 淳⁹、黒川 宏之¹⁰、西田 究³、関根 康人¹¹、辻 健¹⁰、Mark Panning⁶、Lorenz Ralph⁵、Sébastien Rodriguez¹、Antoine Lucas¹ (1.パリシテ大学, パリ地球物理研究所, フランス国立科学研究センター、2.JAXA 宇宙航空研究開発機構 宇宙科学研究所、3.東京大学地震研究所、4.高知大学、5.Applied Physics Laboratory Johns Hopkins University、6.Jet Propulsion Laboratory, California Institute of Technology、7.会津大学　復興創生支援センター 、8.北海道大学　理学研究院 、9.大阪大学、10.東京大学、11.東京工業大学地球生命研究所)

キーワード：惑星科学、タイタン、 地震学

Dragonfly was selected as the 4th New Frontier Mission to explore Titan and investigate its astrobiological potential. Among the suite of instruments on board, the Dragonfly Geophysics and Meteorology Package (DraGMet) is equipped with various geophysical and meteorological sensors to investigate the Titan’s surface and subsurface environment including a vertical short period seismometer and two 2-axes geophone package on its skids. ISAS/JAXA has been developing the short period seismometer for the spacecraft and we will introduce some tests and current expectations for its performances. The instrument will be performing the first seismic observation in the icy world and there are huge uncertainties in its seismicity as well as the noise environment. To be well prepared for the observation, we describe here our approach to evaluate the seismic signal and the noise that we expect on Titan. We mainly focus here on atmospheric signals expected for Titan. We take a similar approach as that for InSight. InSight took numerical models of Mars such as Global Circulation Model (GCM) or Large Eddy Simulation (LES) as inputs and evaluated the ground response. This will enable us to evaluate the expected ambient noise as well as transient seismic events from atmosphere. While atmospheric activities act as a significant source of noise, some transient events such as pressure drops can be detected with seismometer and then be used to study subsurface structure and it would be important to have quantitative evaluation on their detectability. We would also discuss some other possible source that were pointed out in previous studies We compare such signals with known instrumental noise and obtained environmental noise to discuss their detectability.