微惑星上の水-有機反応を模擬した液体フローセルSTXMによるその場反応追跡

• Project Area: Aqua planetology
• Project/Area Number: 18H04461
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Research Institution: Hiroshima University
• Principal Investigator: 薮田 ひかる 広島大学, 理学研究科, 教授 (30530844)
• Project Period (FY): 2018-04-01 – 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: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000); Fiscal Year 2018: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
• Keywords: 走査型透過X線顕微鏡 / 微惑星 / 水質変成 / 有機物 / 液体フローセル / 反応追跡

Outline of Annual Research Achievements

本公募研究の目的は、太陽系始原小天体上における水質変成初期の比較的軽度な条件で短時間に起こる水-有機物反応を観察するために、走査型透過X線顕微鏡（STXM）観察用の液体セルを開発することであった。1年目には、三眼実体顕微鏡を導入し、STXM観察用液体セルを作製する環境を整備した。ただし、本研究の協力機関であるフォトンファクトリーが新しいSTXMビームライン19A/Bを建設する時期と重なっていたため、本研究用にSTXMを使うことができなかった。そのため代わりに、本実験の出発物質の一つである彗星模擬有機物としてHCNポリマー類似の固体有機物の合成を行い、実験の準備を進めた。具体的にはホルムアミドを高温高圧酸分解容器に加え185℃で24時間加熱した。加熱後に得られたタール状の黒褐色物質をメタノールで抽出し、抽出溶液をマトリックス支援レーザー脱離イオン化質量分析法（MALDI-TOFMS） で分析した。その結果、質量スペクトルからシアン化水素 (HCN)の八量体（[HCN]8）に由来する分子イオンピークが顕著に検出された。他にもHCNポリマーに由来すると推測されるイオンピークが検出された。この結果は、ホルムアミドが熱分解することで生じるHCNが重合し、ジアミノマレオニトリル（[HCN]4）を経て[HCN]8構造を形成したことを示唆する。2年目には、大学院生１名が本研究に参加し、上記のHCNポリマー合成法を習得した。様々なpH（pH = 3, ７, 12）、温度（50, 90℃）、時間（24時間 ～１ヶ月）を想定した条件下でHCNポリマーの水熱実験を行った。期間中の実施はかなわなかったが、実験生成物を得ることはできたので、STXM分析を今後行うことで彗星での水質変成における有機物の化学組成の変化を解明できる見込みである。

Research Progress Status

令和元年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和元年度が最終年度であるため、記入しない。

Research Products

• [Journal Article] Shock Vaporization/Devolatilization of Evaporitic Minerals, Halite and Gypsum, in an Open System Investigated by a Two‐Stage Light Gas Gun (2019)
  • Author(s): Kurosawa Kosuke、Moriwaki Ryota、Komatsu Goro、Okamoto Takaya、Sakuma Hiroshi、Yabuta Hikaru、Matsui Takafumi
  • Journal Title: Geophysical Research Letters Volume: 46 Issue: 13 Pages: 7258-7267
  • DOI: 10.1029/2019gl083249
  • NAID: 120006778529
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu?A spinning top?shaped rubble pile (2019)
  • Author(s): Watanabe S.、Hirabayashi M.、Hirata N. et al.
  • Journal Title: Science Volume: 364 Issue: 6437 Pages: 268-272
  • DOI: 10.1126/science.aav8032
  • Peer Reviewed / Open Access / Int'l Joint Research
• [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 Issue: 6437 Pages: 252-252
  • DOI: 10.1126/science.aaw0422
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Further characterization of carbonaceous materials in Hayabusa-returned samples to understand their origin (2019)
  • Author(s): Uesugi Masayuki、Ito Motoo、Yabuta Hikaru、Naraoka Hiroshi、Kitajima Fumio、Takano Yoshinori、Mita Hajime、Kebukawa Yoko、Nakato Aiko、Karouji Yuzuru
  • Journal Title: Meteoritics & Planetary Science Volume: 54 Issue: 3 Pages: 638-666
  • DOI: 10.1111/maps.13236
  • NAID: 120006630615
  • Peer Reviewed
• [Journal Article] STXM-XANES analyses of Murchison meteorite samples captured by aerogel after hypervelocity impacts: A potential implication of organic matter degradation for micrometeoroid collection experiments (2019)
  • Author(s): Kebukawa Yoko、Okudaira Kyoko、Yabuta Hikaru、Hasegawa Sunao、Tabata Makoto、Furukawa Yoshihiro、Ito Motoo、Nakato Aiko、Kilcoyne A. L. David、Kobayashi Kensei、Yokobori Shin-ichi、Imai Eiichi、Kawaguchi Yuko、Yano Hajime、Yamagishi Akihiko
  • Journal Title: GEOCHEMICAL JOURNAL Volume: 53 Issue: 1 Pages: 53-67
  • DOI: 10.2343/geochemj.2.0549
  • NAID: 130007593227
  • ISSN: 0016-7002, 1880-5973
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Prevalence and nature of heating processes in CM and C2-ungrouped chondrites as revealed by insoluble organic matter (2018)
  • Author(s): Quirico E.、Bonal L.、Beck P.、Alexander C.M.O'D.、Yabuta H.、Nakamura T.、Nakato A.、Flandinet L.、Montagnac G.、Schmitt-Kopplin P.、Herd C.D.K.
  • Journal Title: Geochimica et Cosmochimica Acta Volume: 241 Pages: 17-37
  • DOI: 10.1016/j.gca.2018.08.029
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Organic Molecules and Volatiles in Comets (2018)
  • Author(s): Yabuta Hikaru、Sandford Scott A.、Meech Karen J.
  • Journal Title: Elements Volume: 14 Issue: 2 Pages: 101-106
  • DOI: 10.2138/gselements.14.2.101
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Polycyclic aromatic hydrocarbons and aliphatic hydrocarbons in Jbilet Winselwan carbonaceous CM chondrite, a possible analog of asteroid Ryugu’s surface. (2019)
  • Author(s): H. Kato and H. Yabuta
  • Organizer: The 82nd Annual Meeting of Meteoritical Society
  • Int'l Joint Research
• [Presentation] Relationship between visible reflectance at 550 nm and carbon contents in carbonaceous chondrites: At-tempt to estimate the bulk carbon contents of asteroid Ryugu’s surface. (2019)
  • Author(s): H. Yabuta, M. Ikehara, E. Tatsumi, S. Sugita, S. Yamashita, K. Mogi, K. Amano, M. Matsuoka, S. Koba-yashi and T. Nakamura
  • Organizer: The 82nd Annual Meeting of Meteoritical Society
  • Int'l Joint Research
• [Presentation] 「はやぶさ２」および将来のサンプルリターンにおけるSTXMへの期待 (2019)
  • Author(s): 薮田ひかる
  • Organizer: 第3回水惑星学全体会議
• [Presentation] Chemical History of Organic Macromolecules in the Early Solar System: Scientific Strategy and Expected Insights from Asteroid Ryugu (2019)
  • Author(s): H. Yabuta
  • Organizer: Asteroid Science 2019
  • Int'l Joint Research
• [Presentation] Prospects for future analyses of the returned asteroid samples in light of the observation results obtained by Hayabusa2 and OSIRIS-REx missions (2019)
  • Author(s): H. Yabuta, S. Tachibana, M. Abe, M. Yoshikawa, S. Watanabe, Y. Tsuda and Hayabusa2 Science Team
  • Organizer: AGU Fall meeting 2019
  • Int'l Joint Research / Invited
• [Presentation] Landing Site Selection for Hayabusa2: Scientific Evaluation of the Candidate Sites on Asteroid (162173) Ryugu (2019)
  • Author(s): H. Yabuta, S. Watanabe, T. Nakamura, N. Hirata, S. Sugita, T. et al.
  • Organizer: 50th Lunar and Planetary Science Conference
  • Int'l Joint Research
• [Presentation] Overview of the carbonaceous asteroid Ryugu and the first half summary of Hayabusa2 sample return mission. (2019)
  • Author(s): H. Yabuta and Hayabusa2 Team
  • Organizer: XVth Rencontres du Vietnam, LIFE3E’2019: SEARCH FOR LIFE, FROM EARLY EARTH TO EXOPLANETS
  • Int'l Joint Research
• [Presentation] The activities of small bodies exploration missions in Japan and international partners. (2018)
  • Author(s): H. Yabuta, S. Sugita, T. Okada, T. Nakamura, S. Tachibana, T. Arai, M. Kobayashi, M. Yoshikawa, M. Fujimoto, S. Watanabe.
  • Organizer: COSPAR 2018, 42nd Assembly,
  • Int'l Joint Research / Invited
• [Presentation] Hayabusa2 has kicked into full gear: Cosmochemical significance of C-type asteroids in the Solar System formation. (2018)
  • Author(s): H. Yabuta, and Hayabusa2 team
  • Organizer: 50th Annual Meeting of Division for Planetary Sciences
  • Int'l Joint Research / Invited
• [Presentation] Hayabusa2 Landing Site Selection (LSS): Scientific Evaluation on Asteroid Ryugu. (2018)
  • Author(s): H. Yabuta, S. Watanabe, T. Nakamura, N. Hirata, S. Sugita, T. Okada, K. Kitazato, Y. Ishihara, T. Morota, N. Sakatani, K. Matsumoto, K. Wada, S. Tachibana, M. Komatsu, E. Tatsumi, M. Matsuoka, C. Honda, T. Hiroi, S. Senshu, R. Honda, S. Kikuchi, S. Tanaka, A. Miura, T. Yamaguchi, Y. Yamamoto, T. Saiki, Y. Tsuda,
  • Organizer: 50th Annual Meeting of Division for Planetary Sciences
  • Int'l Joint Research
• [Presentation] Scientific Evaluation on the Asteroid Ryugu in Hayabusa2 Landing Site Selection. (2018)
  • Author(s): H. Yabuta, S. Watanabe, T. Nakamura, N. Hirata, S. Sugita, T. Okada, K. Kitazato, Y. Ishihara, T. Morota, N. Sakatani, K. Matsumoto, K. Wada, S. Tachibana, M. Komatsu, E. Tatsumi, M. Matsuoka, C. Honda, T. Hiroi, S. Senshu, R. Honda, S. Kikuchi, S. Tanaka, A. Miura, T. Yamaguchi, Y. Yamamoto, T. Saiki, Y. Tsuda,
  • Organizer: Hayabusa Symposium 2018
  • Int'l Joint Research / Invited
• [Presentation] Hayabusa2 Landing Site Selection: Scientific Evaluation on Asteroid Ryugu. (2018)
  • Author(s): H. Yabuta, S. Watanabe, T. Nakamura, N. Hirata, S. Sugita, T. Okada, K. Kitazato, Y. Ishihara, T. Morota, N. Sakatani, K. Matsumoto, K. Wada, S. Tachibana, M. Komatsu, E. Tatsumi, M. Matsuoka, C. Honda, T. Hiroi, H. Senshu, R. Honda, Y. Yamamoto, N. Ogawa, S. Kikuchi, T. Saiki and Y. Tsuda.
  • Organizer: 2018 AGU Fall meeting
  • Int'l Joint Research
• [Book] Astrobiology: From the Origins of Life to the Search for Extraterrestrial Intelligence (2019)
  • Author(s): Yamagishi, Akihiko, Kakegawa, Takeshi, Usui, Tomohiro (Eds.)
  • Total Pages: 465
  • Publisher: Springer
• [Book] Handbook of Astrobiology (2019)
  • Author(s): Kolb, V. M. (Eds.)
  • Total Pages: 846
  • Publisher: CRC Press
• [Book] Primitive Meteorites and Asteroids: Physical, Chemical and Spectroscopic Observations Paving the Way to Exploration (2018)
  • Author(s): Abreu N. (Ed)
  • Total Pages: 558
  • Publisher: Elsevier