Constructing the model for a stability and evolution of the subsurface ocean in icy bodies

• Project/Area Number: 17K05635
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: Osaka University
• Principal Investigator: Kimura Jun 大阪大学, 理学研究科, 助教 (00536138)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2017: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
• Keywords: 氷天体 / 内部構造 / 進化 / 生命 / アストロバイオロジー / 衛星 / 熱史 / 氷 / 惑星起源・進化 / 惑星探査 / 宇宙科学 / 地球・惑星内部構造

Outline of Final Research Achievements

A numerical model is constructed to explain the long-term evolution of the subsurface ocean in icy bodies. The model is applicable to various internal structures of icy objects, including high-pressure ice, by providing the internal layer structure and initial temperature distribution (solid-liquid state of H2O shell) and the enrichment of long-lived radioisotopes in the rock core. The calculations for Pluto show that the melting viscosity of ice must be greater than 1E15 Pas for the present-day Pluto to have a subsurface ocean, and the initial presence of 1 mass% ammonia extends the subsurface ocean's duration by more than 1 billion years.

Academic Significance and Societal Importance of the Research Achievements

海という大規模な液体水圏の有無とその進化の描像に迫ることは，「生命の起源」という究極の問題への直接的なアプローチのひとつである。特に氷天体という，地球外天体での生命発生環境の候補地としての科学的重要性は，日本惑星科学会が「太陽系における前生命環境の進化―生命圏の誕生・持続に至る条件の解明」として将来目標に掲げているなど，国内外で共通した認識にある。本課題は，太陽系の生命存在可能領域が地球近傍だけではないことを，理論的解析と実証的調査への示唆によって提示する。これは太陽系内天体における宇宙生命論のみならず，系外惑星観測も含めた宇宙の普遍的な生命居住可能性の理解に繋がり，波及効果は大きい。

Research Products

• [Int'l Joint Research] ドイツ航空宇宙研究所(ドイツ)
• [Int'l Joint Research] スウエーデン宇宙物理研究所(スウェーデン)
• [Int'l Joint Research] パリ天文台(フランス)
• [Int'l Joint Research] ドイツ航空宇宙センター(ドイツ)
• [Int'l Joint Research] スウェーデン宇宙物理学研究所(スウェーデン)
• [Int'l Joint Research] パリ天文台(フランス)
• [Journal Article] Stability of the subsurface ocean of pluto (2020)
  • Author(s): J. Kimura and S. Kamata
  • Journal Title: Planetary and Space Science Volume: 181 Pages: 104828-104828
  • DOI: 10.1016/j.pss.2019.104828
  • Peer Reviewed
• [Journal Article] The Ganymede laser altimeter (GALA): key objectives, instrument design, and performance (2019)
  • Author(s): H. Hussmann, K. Lingenauber, R. Kallenbach, K. Enya, N. Thomas, L. M. Lara, C. Althaus, H. Araki, T. Behnke, J. M. Castro-Marin, H. Eisenmenger, T. Gerber, M. H. de la Revilla, C. Huttig, K. Ishibashi, J. Jimenez-Ortega, J. Kimura et al.
  • Journal Title: CEAS Space Journal Volume: -
  • DOI: 10.1007/s12567-019-00282-8
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Hidden Concepts in the History and Philosophy of Origins-of-Life Studies: a Workshop Report (2019)
  • Author(s): Mariscal, C., Barahona, A., Aubert-Kato, N. Nakagawa, M., et al.
  • Journal Title: Origins of Life and Evolution of Biospheres Volume: 49 Pages: 111-145
  • DOI: 10.1007/s11084-019-09580-x
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Plutos ocean is capped and insulated by gas hydrates (2019)
  • Author(s): S. Kamata, F. Nimmo, Y. Sekine, K. Kuramoto, N. Noguchi, J. Kimura, A. Tani
  • Journal Title: Nature Geoscience Volume: 12 Pages: 407-410
  • DOI: 10.1038/s41561-019-0369-8
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Science Objectives of the Ganymede Laser Altimeter (GALA) for the JUICE Mission (2019)
  • Author(s): Jun Kimura, H. Hussmann, S. Kamata, K. Matsumoto, J. Oberst, G. Steinbrugge, A. Stark, K. Gwinner, S. Oshigami, N. Namiki, K. Lingenauber, K. Enya, K. Kuramoto, and S. Sasaki
  • Journal Title: AEROSPACE TECHNOLOGY JAPAN Volume: 17 Issue: 2 Pages: 234-243
  • DOI: 10.2322/tastj.17.234
  • NAID: 130007607430
  • ISSN: 1884-0485
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Active Surface and Interior of Europa as a Potential Deep Habitat (2019)
  • Author(s): Jun Kimura
  • Journal Title: in Astrobiology Volume: - Pages: 383-397
  • DOI: 10.1007/978-981-13-3639-3_24
  • Peer Reviewed
• [Journal Article] The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes (2019)
  • Author(s): Seiji Sugita, R. Honda, T. Morota, S. Kameda, H. Sawada, E. Tatsumi, M. Yamada, C. Honda, Y. Yokota, T. Kouyama, N. Sakatani, K. Ogawa, H. Suzuki, T. Okada, N. Namiki, S. Tanaka, Y. Iijima, K. Yoshioka, M. Hayakawa, Y. Cho, M. Matsuoka, N. Hirata, N. Hirata, H. Miyamoto, Jun Kimura
  • Journal Title: Science Volume: 17 Pages: 1-1
  • DOI: 10.1126/science.aaw0422
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Global classification of lunar reflectance spectra obtained by Kaguya (SELENE): Implication for hidden basaltic materials (2019)
  • Author(s): Hareyama, M., Y. Ishihara, H. Demura, N. Hirata, C. Honda, S. Kamata, Y. Karouji, J. Kimura, T. Morota, H. Nagaoka, R. Nakamura, S. Yamamoto, Y. Yokota, M. Ohtake
  • Journal Title: Icarus Volume: 321 Pages: 407-425
  • DOI: 10.1016/j.icarus.2018.11.016
  • Peer Reviewed
• [Journal Article] Orbital evolution of Saturn's mid-sized moons and the tidal heating of Enceladus (2019)
  • Author(s): Ayano Nakajima, S. Ida, Jun Kimura, and R. Brasser
  • Journal Title: Icarus Volume: 317 Pages: 570-582
  • DOI: 10.1016/j.icarus.2018.08.030
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Feasibility of the exploration of the subsurface structures of Jupiter's icy moons by interference of Jovian hectometric and decametric radiation (2018)
  • Author(s): Atsushi Kumamoto, Y. Kasaba, F. Tsuchiya, H. Misawa, H. Kita, W. Puccioy, J.-E. Wahlundy, J. Bergmany, B. Cecconi, Y. Gotox, Jun Kimura
  • Journal Title: Planetary Radio Emissions VIII Volume: - Pages: 127-136
  • DOI: 10.1553/pre8s127
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Science Objectives of the Ganymede Laser Altimeter (GALA) for the JUICE mission (2018)
  • Author(s): Jun Kimura et al.
  • Journal Title: Transactions of the Japan Society for Aeronautical and Space Sciences Volume: -
  • NAID: 130007607430
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Feasibility of the exploration of the subsurface structures of Jupiter's icy moons by interference of Jovian hectometric and decametric radiation (2018)
  • Author(s): Atsushi Kumamoto, Jun Kimura et al.
  • Journal Title: Planetary Radio Emissions VIII Volume: -
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] 木星氷衛星に非H2O氷を探す (2020)
  • Author(s): 木村淳，高木聖子，松尾太郎
  • Organizer: 第7回衛星系研究会
• [Presentation] 太陽系天体の宇宙風化再現実験に向けた汎用プラズマ照射装置の開発 (2020)
  • Author(s): 木村 智樹, 木村 淳, 吉岡 和夫, 村上 豪, 寺田 直樹, 臼井 英之, 西野 真木, 横田 勝一郎, 三宅 洋平
  • Organizer: 第7回衛星系研究会
• [Presentation] Tectonics on icy bodies: morphology and origin, Fracture and Geomorphology (2019)
  • Author(s): Jun Kimura
  • Organizer: Osaka workshop for nonequilibrium physics
  • Int'l Joint Research / Invited
• [Presentation] Explorations and current understandings for subsurface ocean of icy bodies (2019)
  • Author(s): Jun Kimura
  • Organizer: JpGU Meeting 2019
  • Int'l Joint Research / Invited
• [Presentation] An interior structure model of Pluto resolving its mysteries (2019)
  • Author(s): Shunichi Kamata, Francis Nimmo, Yasuhito Sekine, Kiyoshi Kuramoto, Naoki Noguchi, Jun Kimura, Atsushi Tani
  • Organizer: JpGU Meeting 2019
  • Int'l Joint Research
• [Presentation] Inclusion of brine into icy shell of Enceladus (2019)
  • Author(s): Ryusuke Nishitani, Atsushi Tani, Sho Sasaki and Jun Kimura
  • Organizer: JpGU Meeting 2019
  • Int'l Joint Research
• [Presentation] Stability of the subsurface ocean of Pluto (2019)
  • Author(s): Jun Kimura, and Shunichi Kamata
  • Organizer: AOGS2019
  • Int'l Joint Research
• [Presentation] 土星衛星EnceladusとMimasにおけるメタンハイドレートの形成と熱進化 (2019)
  • Author(s): 西谷隆介，木村淳，谷篤史，佐々木晶
  • Organizer: 日本惑星科学会2019年秋季講演会
• [Presentation] 潮汐変形と位相の遅れを考慮したGanymedeの強制秤動 (2019)
  • Author(s): 小島晋一郎，木村淳，鎌田俊一
  • Organizer: 日本惑星科学会2019年秋季講演会
• [Presentation] 冥王星の窒素氷の昇華と凝結による反射率分布の変化 (2019)
  • Author(s): 松井弥志，木村淳
  • Organizer: 日本惑星科学会2019年秋季講演会
• [Presentation] 太陽系天体の宇宙風化再現実験に向けた汎用プラズマ照射装置の開発 (2019)
  • Author(s): 木村 智樹, 木村 淳, 吉岡 和夫, 村上 豪, 寺田 直樹, 臼井 英之, 西野 真木, 横田 勝一郎, 三宅 洋平
  • Organizer: 第146回 SGEPSS総会および講演会
• [Presentation] Science targets of the GAnymede Laser Altimeter (GALA) for the JUICE mission (2019)
  • Author(s): 木村淳，並木則行，鎌田俊一，松本晃治，押上祥子，塩谷圭吾，倉本圭ほか
  • Organizer: JpGU Meeting 2019
• [Presentation] Forced libration of Ganymede including the visco-elastic tidal deformation (2019)
  • Author(s): 小島晋一郎, 木村淳，鎌田俊一
  • Organizer: JpGU Meeting 2019
• [Presentation] Evolution of Pluto's surface albedo due to sublimation and condensation of ice (2019)
  • Author(s): 松井弥志，木村淳
  • Organizer: JpGU Meeting 2019
• [Presentation] Interior evolution of Galilean satellites (2019)
  • Author(s): Shunichi Kamata and Jun Kimura
  • Organizer: Symposium on Planetary Sciences 2019
  • Int'l Joint Research / Invited
• [Presentation] Clues from above: Topographic signatures of icy surface dynamics using laser altimetry and implications for the Ganymede laser altimeter (GALA) (2019)
  • Author(s): Catherine Walker, Jun Kimura, and Alex Gardner
  • Organizer: 50th LPSC
  • Int'l Joint Research
• [Presentation] Thermal evolution and stability of subsurface ocean in Pluto Metallic core and thermal evolution of icy bodies (2018)
  • Author(s): Jun Kimura
  • Organizer: JpGU Meeting 2018
  • Int'l Joint Research / Invited
• [Presentation] The Ganymede Laser Altimeter (GALA) for ESA’s Jupiter Icy Moons Explorer (JUICE) Mission (2018)
  • Author(s): Hauke Hussmann, Kay Lingenauber, Reinald Kallenbach, Jurgen Oberst, Keigo Enya, Masanori Kobayashi, Noriyuki Namiki, Jun Kimura, N. Thomas, L. Lara, Gregor Steinbrugge, Alexander Stark, Fabian Luedicke, Thomas Behnke, Christian Althaus, Simone Del Togno, Belinda Borgs, Harald Michaelis, Judit Janchen
  • Organizer: EPSC 2018
  • Int'l Joint Research
• [Presentation] Evolution of Pluto’s subsurface ocean and constraint on its interior (2018)
  • Author(s): Jun Kimura, and Shunichi Kamata
  • Organizer: AOGS2018
  • Int'l Joint Research
• [Presentation] Volume Expansion of Ganymede due to Temperature Change and Phase Change of Ices (2018)
  • Author(s): Yoda Masahiro, Jun Kimura, Yashito Sekine, Kei Kurita
  • Organizer: Cryovolcanism in the Solar System Workshop
  • Int'l Joint Research
• [Presentation] Evolution of subsurface ocean of Pluto and constraint on its interior (2018)
  • Author(s): Jun Kimura and Shunichi Kamata
  • Organizer: JpGU Meeting 2018
  • Int'l Joint Research
• [Presentation] Inclusion of ammonium ion into clathrate hydrate in subsurface ocean of icy moon (2018)
  • Author(s): Ryusuke Nishitani, Jun Kimura, Atsushi Tani, Sho Sasaki
  • Organizer: 14th International Conference on the Physics and Chemistry of Ice
  • Int'l Joint Research
• [Presentation] JUICE 搭載ガニメデレーザ高度計 (GALA)－ 概要および日本チーム開発状況 (2018)
  • Author(s): 塩谷圭吾，並木則行，小林正規，木村淳
  • Organizer: 日本惑星科学会2018年秋季講演会
• [Presentation] 冥王星表面の氷の昇華と凝結による反射率の変化 (2018)
  • Author(s): 松井弥志，木村淳
  • Organizer: 日本惑星科学会2018年秋季講演会
• [Presentation] 土星衛星エンセラダス熱進化におけるクラスレートハイドレートの役割 (2018)
  • Author(s): 西谷隆介，木村淳，谷篤史，佐々木晶
  • Organizer: 日本惑星科学会2018年秋季講演会
• [Presentation] 冥王星地下海の安定性と進化 (2018)
  • Author(s): 木村淳，鎌田俊一
  • Organizer: 日本惑星科学会2018年秋季講演会
• [Presentation] 木星圏探査機JUICE 搭載レーザ高度計（GALA）の科学目標 (2018)
  • Author(s): 木村淳，並木則行，鎌田俊一，松本晃治，押上祥子，塩谷圭吾，倉本圭
  • Organizer: 第144回 SGEPSS総会および講演会
• [Presentation] 氷天体熱進化に対するクラスレートハイドレートの影響 (2018)
  • Author(s): 西谷隆介，木村淳，谷篤史，佐々木晶
  • Organizer: 第6回衛星系研究会
• [Presentation] 土星中型衛星の軌道進化 (2018)
  • Author(s): 中島彩乃，木村淳，井田茂
  • Organizer: 第6回衛星系研究会
• [Presentation] 衛星研究の現状と将来展望 (2018)
  • Author(s): 木村淳
  • Organizer: 第19回惑星圏研究会
  • Invited
• [Presentation] Thermal history and stability of subsurface ocean in Pluto (2017)
  • Author(s): Jun Kimura
  • Organizer: AOGS 2017 Annual Meeting
  • Int'l Joint Research
• [Presentation] Science Objectives of the Ganymede Laser Altimeter (GALA) for the JUICE mission (2017)
  • Author(s): Jun Kimura
  • Organizer: Joint Conference: 31st ISTS, 26th ISSFD and 8th NSAT
  • Int'l Joint Research
• [Presentation] Thermal evolution and stability of subsurface ocean in Pluto (2017)
  • Author(s): Jun Kimura
  • Organizer: JpGU-AGU Joint Meeting 2017
  • Int'l Joint Research
• [Presentation] JUICE 搭載ガニメデレーザ高度計(GALA) で目指すサイエンス (2017)
  • Author(s): 木村淳
  • Organizer: 日本惑星科学会2017年秋季講演会
• [Presentation] JUICE/GALA-J(2): JUICE搭載ガニメデレーザ高度計（GALA）が木星氷衛星で目指す科学 (2017)
  • Author(s): 木村淳
  • Organizer: JpGU-AGU Joint Meeting 2017
• [Book] 氷天体，小天体，衛星，リング；ハビタブルゾーン；生命存在環境としての氷天体地下海 in 太陽・惑星系と地球 (2019)
  • Author(s): 木村淳
  • Total Pages: 400
  • Publisher: 共立出版
  • ISBN: 9784320047099