Development of the technique for the viscosity measurement of brine in the icy satellites

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K21890
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 17:Earth and planetary science and related fields
• Research Institution: Tohoku University
• Principal Investigator: Suzuki Akio 東北大学, 理学研究科, 准教授 (20281975)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 衛星内部海 / 氷火山 / 塩水溶液 / 高圧力 / 粘度

Outline of Final Research Achievements

We developed an experimental system to measure the viscosity of brine in the icy satellite. Viscosity was measured by the falling sphere method. To measure the viscosity with changing the pressure and the temperature, we installed a rotation stage on which a high-pressure cell is loaded. After a sphere falls to the bottom end, we observe the falling sphere again by turning over the cell on the rotation stage. We also assembled a cooling-unit to cool the sample in the chamber. By developing this system, we are now ready to measure the viscosity of the brine under the pressure and the temperature conditions of the icy satellites.

Free Research Field

量子ビーム地球科学

Academic Significance and Societal Importance of the Research Achievements

木星以遠の外惑星に存在する氷衛星の内部には溶けた領域があり、内部海と呼ばれている。内部海は地球以外で液体の水が存在する領域であり、水は生命活動に不可欠であるため、内部海では原始的な生命体が発生している可能性がある。このため、内部海の解明は生命起源にも関係しているため学術的意義や社会的意義は大きい。本研究によって、内部海の形成・進化に重要な、海の粘度を実際の内部海環境で測定できるようになった。