粒子計算手法による衝突掘削物の放出角度決定機構の解明

• Project/Area Number: 19K03955
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17010:Space and planetary sciences-related
• Research Institution: Chiba Institute of Technology
• Principal Investigator: 和田 浩二 千葉工業大学, 惑星探査研究センター, 主席研究員 (10396856)
• Project Period (FY): 2019-04-01 – 2025-03-31
• Project Status: Granted (Fiscal Year 2023)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2021: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: 天体衝突 / 数値シミュレーション / イジェクタ / 掘削流 / 宇宙衝突実験 / 固体惑星探査 / 衝突シミュレーション / 小惑星

Outline of Research at the Start

固体天体上に隕石のような天体が衝突すると，衝突クレータが形成される．その際掘削された物質が放出される(放出物はイジェクタと呼ばれる) が，その放出角度を決定する機構は衝突探査によって天体の表層・内部状態を推定するうえで必要であるが，十分理解されていない．本研究では，衝突数値シミュレーションを通じて，衝突掘削物の放出角度が衝突・標的環境条件にどう依存するかを明らかにしてモデル化する．

Outline of Annual Research Achievements

固体天体上に隕石のような天体が衝突すると，衝突クレータが形成される．その際掘削された物質が放出される(放出物はイジェクタと呼ばれる) が，その放出角度を決定する機構は衝突探査によって天体の表層・内部状態を推定するうえで必要であるが，十分理解されていない．本研究では，衝突数値シミュレーションを通じて，衝突掘削物の放出角度が衝突・標的環境条件にどう依存するかを明らかにしてモデル化する．
2023年度においては，貴重な観測データである「はやぶさ２」搭載衝突体による小惑星リュウグウへの衝突時に発生したイジェクタカーテンの解析を引き続き進めており，撮像機器である分離カメラの解析が終了し論文化され，撮像データの較正準備が整いつつあり，現在論文化を目指して解析中である．また，同時に数値シミュレーションに基づくモデル化も進めている．

Current Status of Research Progress

3: Progress in research has been slightly delayed.

Reason

2023年度は数値シミュレーションの解析ほか進めているが，大会運営委員長を務める地球惑星科学連合大会の対応準備に忙殺されたという事情もあって，計算結果の整理・解析が十分に進められていない．一方で，「はやぶさ２」における本物の小惑星上での衝突実験の解析が大きく進展し，数値シミュレーションと合わせてより大きな成果としてまとめられると期待される．

Strategy for Future Research Activity

2024年度は，これまでのシミュレーション結果の整理・解析を進めるととものに，「はやぶさ２」の宇宙衝突実験で得られた画像データを較正したうえで解析しモデルと比較する．その結果，掘削流をはじめ圧力・密度分布や圧縮・非圧縮領域の把握および粒子の運動制約など物理的描像を明確にする予定である．

Research Products

• [Int'l Joint Research] University of Colorado Boulder(米国)
• [Int'l Joint Research] Institute for Basic Science(韓国)
• [Int'l Joint Research] DLR(ドイツ)
• [Int'l Joint Research] CNES/コートダジュール 観測所/University of Lorraine(フランス)
• [Int'l Joint Research] University of Arizona/NASA/Carnegie Institution for Science(米国)
• [Int'l Joint Research] Instituto de Astrofisica de Canarias(スペイン)
• [Int'l Joint Research] University of Liverpool(英国)
• [Int'l Joint Research]
• [Int'l Joint Research] Manipal Centre for Natural Sciences(インド)
• [Journal Article] Simultaneous geometric calibration and orbit-attitude determination of Hayabusa2's deployable camera (DCAM3) (2024)
  • Author(s): Kikuchi S.、Shirai K.、Ishibashi K.、Wada K. et al.
  • Journal Title: Advances in Space Research Volume: - Issue: 2 Pages: 899-936
  • DOI: 10.1016/j.asr.2024.04.057
  • Peer Reviewed / Open Access
• [Journal Article] Preliminary design of the Hayabusa2 extended mission to the fast-rotating asteroid 1998 KY26 (2023)
  • Author(s): Kikuchi Shota、Mimasu Yuya、Takei Yuto、Saiki Takanao、Scheeres Daniel J.、Hirabayashi Masatoshi、Wada Koji、Yoshikawa Makoto、Watanabe Sei-ichiro、Tanaka Satoshi、Tsuda Yuichi
  • Journal Title: Acta Astronautica Volume: 211 Pages: 295-315
  • DOI: 10.1016/j.actaastro.2023.06.010
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Phase ratio in single-scattering dust particles: Implication to future DESTINY+ study of asteroid (3200) Phaethon (2023)
  • Author(s): Zubko Evgenij、Wada Koji
  • Journal Title: Icarus Volume: 404 Pages: 115652-115652
  • DOI: 10.1016/j.icarus.2023.115652
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Collisional Growth and Fragmentation of Dust Aggregates. II. Mass Distribution of Icy Fragments (2023)
  • Author(s): Hasegawa Yukihiko、Suzuki Takeru K.、Tanaka Hidekazu、Kobayashi Hiroshi、Wada Koji
  • Journal Title: The Astrophysical Journal Volume: 944 Issue: 1 Pages: 38-38
  • DOI: 10.3847/1538-4357/acadda
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Particle size distributions inside and around the artificial crater produced by the Hayabusa2 impact experiment on Ryugu (2022)
  • Author(s): Ogawa K.、Sakatani N.、Kadono T.、Arakawa M.、Honda R.、Wada K.、et al.
  • Journal Title: Earth, Planets and Space Volume: 74 Issue: 1 Pages: 153-153
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  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Effect of projectile shape and interior structure on crater size in strength regime (2022)
  • Author(s): Kadono T.、Arakawa M.、Tsujido S.、Yasui M.、Hasegawa S.、Kurosawa K.、Shirai K.、Okamoto C.、Ogawa K.、Iijima Y.、Shimaki Y.、Wada K.
  • Journal Title: Earth, Planets and Space Volume: 74 Issue: 1 Pages: 131-131
  • DOI: 10.1186/s40623-022-01690-7
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Site selection for the Hayabusa2 artificial cratering and subsurface material sampling on Ryugu (2022)
  • Author(s): Kikuchi Shota、Watanabe Sei-ichiro、Wada Koji、Saiki Takanao、Yabuta Hikaru、Sugita Seiji、Abe Masanao、Arakawa Masahiko、Cho Yuichiro、Hayakawa Masahiko et al.
  • Journal Title: Planetary and Space Science Volume: 219 Pages: 105519-105519
  • DOI: 10.1016/j.pss.2022.105519
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth (2022)
  • Author(s): Tachibana S.、Abe M. et al.
  • Journal Title: Science Volume: 375 Issue: 6584 Pages: 1011-1016
  • DOI: 10.1126/science.abj8624
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Preliminary analysis of the Hayabusa2 samples returned from C-type asteroid Ryugu (2021)
  • Author(s): Yada Toru、Abe Masanao、et al.
  • Journal Title: Nature Astronomy Volume: 6 Issue: 2 Pages: 214-220
  • DOI: 10.1038/s41550-021-01550-6
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Resurfacing processes on asteroid (162173) Ryugu caused by an artificial impact of Hayabusa2's Small Carry-on Impactor (2021)
  • Author(s): Honda Rie、Arakawa Masahiko、Shimaki Yuri、Shirai Kei、Yokota Yasuhiro、Kadono Toshihiko、Wada Koji、et al.
  • Journal Title: Icarus Volume: 366 Pages: 114530-114530
  • DOI: 10.1016/j.icarus.2021.114530
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Anomalously porous boulders on (162173) Ryugu as primordial materials from its parent body (2021)
  • Author(s): N. Sakatani, S. Tanaka, T. Okada, et al.
  • Journal Title: Nature Astronomy Volume: － Issue: 8 Pages: 766-774
  • DOI: 10.1038/s41550-021-01371-7
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Surface environment of Phobos and Phobos simulant UTPS (2021)
  • Author(s): Miyamoto Hideaki、Niihara Takafumi、Wada Koji、et al.
  • Journal Title: Earth, Planets and Space Volume: 73 Issue: 1 Pages: 214-214
  • DOI: 10.1186/s40623-021-01406-3
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Size of particles ejected from an artificial impact crater on asteroid 162173 Ryugu (2021)
  • Author(s): Wada K.、Ishibashi K.、Kimura H.、Arakawa M.、Sawada H.、Ogawa K.、Shirai K.、Honda R.、Iijima Y.、Kadono T.、Sakatani N.、Mimasu Y.、Toda T.、Shimaki Y.、Nakazawa S.、Hayakawa H.、Saiki T.、Takagi Y.、Imamura H.、Okamoto C.、Hayakawa M.、Hirata N.、Yano H.
  • Journal Title: Astronomy & Astrophysics Volume: 647 Pages: A43-A43
  • DOI: 10.1051/0004-6361/202039777
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Collisional history of Ryugu’s parent body from bright surface boulders (2021)
  • Author(s): Tatsumi E.、Sugimoto C.、Riu L.、... Yabuta, H. ... et al. (75人中67番目)
  • Journal Title: Nature Astronomy Volume: 5 Issue: 1 Pages: 39-45
  • DOI: 10.1038/s41550-020-1179-z
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Thermally altered subsurface material of asteroid (162173) Ryugu (2021)
  • Author(s): Kitazato K.、Milliken R. E.、Iwata T. .. Yabuta, H. ... et al. (101人中76番目)
  • Journal Title: Nature Astronomy Volume: 5 Issue: 3 Pages: 246-250
  • DOI: 10.1038/s41550-020-01271-2
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Impact Experiment on Asteroid (162173) Ryugu: Structure beneath the Impact Point Revealed by In Situ Observations of the Ejecta Curtain (2020)
  • Author(s): Kadono Toshihiko、Arakawa Masahiko、Honda Rie、Ishibashi Ko、Ogawa Kazunori、Sakatani Naoya、Sawada Hirotaka、Shimaki Yuri、Shirai Kei、Sugita Seiji、Wada Koji
  • Journal Title: The Astrophysical Journal Volume: 899 Issue: 1 Pages: L22-L22
  • DOI: 10.3847/2041-8213/aba949
  • Peer Reviewed
• [Journal Article] Sample collection from asteroid (162173) Ryugu by Hayabusa2: Implications for surface evolution (2020)
  • Author(s): Morota, T., Sugita, S., Cho, Y., Kanamaru, M., Tatsumi, E., Sakatani, N., Honda, R., Hirata, N. et al.
  • Journal Title: Science Volume: 368 Issue: 6491 Pages: 654-659
  • DOI: 10.1126/science.aaz6306
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Is water ice an efficient facilitator for dust coagulation? (2020)
  • Author(s): Kimura Hiroshi、Wada Koji、Kobayashi Hiroshi、Senshu Hiroki、Hirai Takayuki、Yoshida Fumi、Kobayashi Masanori、Hong Peng K、Arai Tomoko、Ishibashi Ko、Yamada Manabu
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 498 Issue: 2 Pages: 1801-1813
  • DOI: 10.1093/mnras/staa2467
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] An artificial impact on the asteroid 162173 Ryugu formed a crater in the gravity-dominated regime (2020)
  • Author(s): Arakawa, M., Saiki, T., Wada, K., Ogawa, K., Kadono, T., Shirai, K., Sawada, H., Ishibashi, K., Honda, R., Sakatani, N., Iijima, Y., Okamoto, C., Yano, H., Takagi, Y., Hayakawa, M., Michel, P., Jutzi, M., Shimaki, Y., Kimura, S., Mimasu, Y., Toda, T., Imamura, H., Nakazawa, S., Hayakawa, H., Sugita, S., et al.
  • Journal Title: Science Volume: 368 Issue: 6486 Pages: 67-71
  • DOI: 10.1126/science.aaz1701
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Highly porous nature of a primitive asteroid revealed by thermal imaging (2020)
  • Author(s): T.Okada, T.Fukuhara, S.Tanaka, M.Taguchi, T.Arai, H.Senshu, N.Sakatani, Y.Shimaki, H.Demura, Y.Ogawa, K.Suko, T.Sekiguchi, T.Kouyama, J.Takita, T.Matsunaga, T.Imamura, T.Wada, S.Hasegawa, J.Helbert, T.G.Muller, A.Hagermann, J.Biele, M.Grott, M.Hamm, M.Delbo, N.Hirata, N.Hirata, Y.Yamamoto, A.Miura, et al.
  • Journal Title: Nature Volume: 579 Issue: 7800 Pages: 518-522
  • DOI: 10.1038/s41586-020-2102-6
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A generalised methodology for analytic construction of 1:1 resonances around irregular bodies: Application to the asteroid Ryugu’s ejecta dynamics (2020)
  • Author(s): Soldini Stefania、Takanao Saiki、Ikeda Hitoshi、Wada Koji、Yuichi Tsuda、Hirata Naru、Hirata Naoyuki
  • Journal Title: Planetary and Space Science Volume: 180 Pages: 104740-104740
  • DOI: 10.1016/j.pss.2019.104740
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Ballistic deployment from quasi-satellite orbits around Phobos under realistic dynamical and surface environment constraints (2019)
  • Author(s): Celik Onur、Baresi Nicola、Ballouz Ronald-Louis、Ogawa Kazunori、Wada Koji、Kawakatsu Yasuhiro
  • Journal Title: Planetary and Space Science Volume: 178 Pages: 104693-104693
  • DOI: 10.1016/j.pss.2019.06.010
  • Peer Reviewed / Int'l Joint Research
• [Presentation] 火星衛星探査計画MMXの到着前着陸候補地域選定 (2023)
  • Author(s): 和田浩二，他
  • Organizer: 第67回宇宙科学技術連合講演会
• [Presentation] エジェクタカーテン中のパターンと標的粒子のサイズ分布 (2023)
  • Author(s): 門野敏彦、荒川大，荒川政彦，笠木祥喜，黒澤耕介， 嶌生有理，末次竜，杉田精二，鈴 木絢子， 中惇太，中村昭子，永山秀一，長谷川直， 春山純一，松村倫太郎，山本聡，和田浩二
  • Organizer: 日本惑星科学会2023年秋季講演会
• [Presentation] PHOTOMETRIC PARAMETERS OF THE EJECTA DEPOSITS AROUND AN ARTIFICIAL CRATER ON ASTEROID RYUGU (2023)
  • Author(s): Y. Yokota, ..., K. Wada etal.
  • Organizer: Lunar Planet. Sci. Conf. 54th
  • Int'l Joint Research
• [Presentation] Particle size of Ryugu regolith inferred from SCI impact cratering (2021)
  • Author(s): Koji Wada, K. Ishibashi, H. Kimura, M. Arakawa, H. Sawada, K. Ogawa, K. Shirai, R. Honda, Y. Iijima, T. Kadono, N. Sakatani, Y. Mimasu, T. Toda, Y. Shimaki, S. Nakazawa, H. Hayakawa, T. Saiki, Y. Takagi, H. Imamura, C. Okamoto, M. Hayakawa, N. Hirata, and H. Yano
  • Organizer: Dust Workshop Reloaded
  • Int'l Joint Research / Invited
• [Presentation] はやぶさ2衝突装置による科学的成果 (2021)
  • Author(s): 和田浩二, はやぶさ２ SCI/DCAM3 チーム
  • Organizer: 日本機械学会2021 年度年次大会
  • Invited
• [Presentation] はやぶさ2 の統合サイエンス (2021)
  • Author(s): 渡邊誠一郎, 薮田ひかる, 和田浩二, 平田成, 平田直之, 嶌生有理, 野口里奈, 杉田精司, 北里宏平, 岡田達明, 並木則行, 橘省吾, 荒川政彦, 田中智
  • Organizer: 日本地球惑星科学連合2021年大会
• [Presentation] Particle size of Ryugu’s subsurface layer inferred from observation of SCI crater’s ejecta curtain (2021)
  • Author(s): 和田浩二, 石橋高, 木村宏, 荒川政彦, 澤田弘崇, 小川和律, 白井慶, 本田理恵, 飯島祐一, 門 野敏彦, 坂谷尚哉, 三桝裕也, 戸田知朗, 嶌生有理, 中澤暁, 早川基, 佐伯孝尚, 高木靖彦, 今村裕志, 岡本千里, 早川雅彦, 平田成, 矢野創
  • Organizer: 日本地球惑星科学連合2021年大会
• [Presentation] Particle size of Ryugu's subsurface layer inferred from ejecta curtainof SCI crater observed by DCAM3 (2021)
  • Author(s): Koji Wada et al.
  • Organizer: IDP2021
  • Int'l Joint Research
• [Presentation] The size of ejecta particles of the artificial impact crater formed by Hayabusa2 Small Carry-on Impactor (2020)
  • Author(s): Koji Wada et al.
  • Organizer: JpGU-AGU Joint Meeting 2020: Virtual
  • Int'l Joint Research
• [Presentation] 「はやぶさ２」搭載分離カメラDCAM3により SCI衝突実験時に観測された放出ボルダ (2020)
  • Author(s): 石橋 高，白井 慶，和田 浩二，小川 和律，坂谷 尚哉，嶌生 有理，横田 康弘，本田 理恵，門野 敏彦，荒川 政彦
  • Organizer: 惑星科学会秋季講演会
• [Presentation] Space impact experiment on Ryugu: Pattern of ejecta curtain and the properties of particles in surface and subsurface (2020)
  • Author(s): Toshihiko Kadono, Masahiko Arakawa, Rie Honda, Ko Ishibashi, Kazunori Ogawa, Naoya Sakatani, Yuri Shimaki, Seiji Sugita, Koji Wada
  • Organizer: JpGU-AGU Joint Meeting 2020: Virtual
  • Int'l Joint Research / Invited
• [Presentation] Artificial impact crater formed by Hayabusa2 small carry-on impactor on the surface of asteroid Ryugu (2019)
  • Author(s): M. Arakawa, T. Saiki, T. Kadono, Y. Takagi, K. Wada(34名中5番目), et al.
  • Organizer: American Geophysical Union Fall Meeting
  • Int'l Joint Research
• [Presentation] Space Impact Experiment on Ryugu: Ejecta Curtain Observed by DCAM3 (2019)
  • Author(s): M. Arakawa, K. Shirai, H. Sawada, R. Honda, K. Ishibashi, K. Wada, T. Kadono, Y. Iijima, N. Sakatani, Y. Shimaki, Y. Mimasu, T. Toda, S. Nakazawa, H. Hayakawa, T. Saiki, Y. Takagi, H. Imamura, C. Okamoto1, H. Yano, M. Hayakawa, N. Hirata
  • Organizer: Asteroid Science in the Age of Hayabusa2 and OSIRIS-REx
  • Int'l Joint Research
• [Presentation] The structure and strength of Ryugu’s surface layer inferred from the SCI crater (2019)
  • Author(s): M. Arakawa, T. Saiki, K. Wada(68名中3番目), et al.
  • Organizer: IRSG & M-scale 3rd Joint Meeting
  • Int'l Joint Research
• [Presentation] First result of Hayabusa2 impact experiment on Ryugu (2019)
  • Author(s): Arakawa, M., Saiki, T., Kadono, T., Takagi, Y., Wada, K.(34名中5番目), et al.
  • Organizer: EPSC-DPS Joint Meeting 2019,
  • Int'l Joint Research
• [Presentation] 「はやぶさ２」による小惑星リュウグウ上 での宇宙衝突実験 (2019)
  • Author(s): 和田浩二，荒川政彦，はやぶさ２プロジェクト
  • Organizer: 第12 回構造物の衝撃問題に関するシンポジウム
  • Invited
• [Presentation] SCI クレータから放出されたイジェクタ粒子のサイズ推定 (2019)
  • Author(s): 和田浩二，他22名
  • Organizer: 第15 回衝突研究会「天体の衝突物理の解明(XIV)」
• [Presentation] はやぶさ２衝突装置によって生成されたイジェクタカーテンの解析から推定される小惑星リュウグウの表層物性 (2019)
  • Author(s): 和田浩二，他22名
  • Organizer: 2019 年日本惑星科学会秋季講演会