Surface evolution of small bodies of the solar system by space weatheirng and thermal fatigue

• Project/Area Number: 18H01267
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 17010:Space and planetary sciences-related
• Research Institution: Osaka University
• Principal Investigator: Sasaki Sho 大阪大学, 理学研究科, 教授 (10183823)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥17,810,000 (Direct Cost: ¥13,700,000、Indirect Cost: ¥4,110,000); Fiscal Year 2020: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000); Fiscal Year 2019: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000); Fiscal Year 2018: ¥11,050,000 (Direct Cost: ¥8,500,000、Indirect Cost: ¥2,550,000)
• Keywords: 宇宙風化作用 / 熱疲労 / はやぶさ２ / 反射スペクトル / 炭素質隕石 / 暗化 / 含水鉱物 / リュウグウ / ボルダー

Outline of Final Research Achievements

The current diffuse reflection measurement system was modified to measure down to 3.4 microns, and measurements of the CM2 carbonaceous meteorite show a slight weakening of the 3-μm absorption band after laser irradiation and an overall weakening and reddening of the spectrum. The color of recently formed craters is relatively blue in Ryugu (Morota et al., 2020). This is consistent with our results.
Regarding ultraviolet irradiation, an interesting result is that the visible region of olivine darkens in a short period of time. Even in space, a reflectance decrease of several 10% is expected after a few days of irradiation.　Cracks in the rocks on the surface of Ryugu are predominantly in the north-south direction, which may be due to thermal fatigue.

Academic Significance and Societal Importance of the Research Achievements

はやぶさ２による炭素質小惑星リュウグウの探査は、地球惑星科学や宇宙工学にとどまらず、広い分野にインパクトを与えている。科学成果を最大化するために、ミッションデータ解析や地上実験のサポートは意義が高く不可欠である。我々のCM2炭素質隕石の測定では、レーザー照射後は3μmの吸収帯が少し弱くなること、全体的にスペクトルが弱く赤化する。最近形成されたクレーターの色はリュウグウでは相対的に青く(Morota et al., 2020)これは、我々の結果と整合的であり、研究の学術的意義の高さを示す。

Research Products

• [Int'l Joint Research] ブラウン大学/オーバーン大学(米国)
• [Int'l Joint Research] コートダジュール天文台(フランス)
• [Int'l Joint Research] ブラウン大学(米国)
• [Int'l Joint Research] カナリア天体物理学研究所(スペイン)
• [Journal Article] Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu (2022)
  • Author(s): Michikami Tatsuhiro、Hagermann Axel、Morota Tomokatsu、et al.
  • Journal Title: Icarus Volume: 381 Pages: 115007-115007
  • DOI: 10.1016/j.icarus.2022.115007
  • 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] YORP Effect on Asteroid 162173 Ryugu: Implications for the Dynamical History (2021)
  • Author(s): Kanamaru Masanori、Sasaki Sho、Morota Tomokatsu、Cho Yuichiro、Tatsumi Eri、Hirabayashi Masatoshi、Hirata Naru、Senshu Hiroki、Shimaki Yuri、Sakatani Naoya、Tanaka Satoshi、Okada Tatsuaki、Usui Tomohiro、Sugita Seiji、Watanabe Sei‐ichiro
  • Journal Title: Journal of Geophysical Research: Planets Volume: 126 Issue: 12
  • DOI: 10.1029/2021je006863
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Spectrally blue hydrated parent body of asteroid (162173) Ryugu (2021)
  • Author(s): Tatsumi Eri、Sakatani Naoya、Riu Lucie、Matsuoka Moe、et al.
  • Journal Title: Nature Communications Volume: 12 Issue: 1 Pages: 5837-5837
  • DOI: 10.1038/s41467-021-26071-8
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Science operation plan of Phobos and Deimos from the MMX spacecraft (2021)
  • Author(s): Nakamura Tomoki、Ikeda Hitoshi、Kouyama Toru、Nakagawa Hiromu et al.
  • Journal Title: Earth, Planets and Space Volume: 73 Issue: 1 Pages: 227-227
  • DOI: 10.1186/s40623-021-01546-6
  • Peer Reviewed / Open Access / 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] 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] Dynamic precise orbit determination of Hayabusa2 using laser altimeter (LIDAR) and image tracking data sets (2020)
  • Author(s): Yamamoto, K., Otsubo, T., Matsumoto, K., Noda, H., Namiki, N., Takeuchi, H., Ikeda, H., Yoshikawa, M., Yamamoto, Y., Senshu, H., Mizuno, T., Hirata, N. et al.
  • Journal Title: Earth, Planets and Space Volume: 72 Issue: 1 Pages: 85-85
  • DOI: 10.1186/s40623-020-01213-2
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Improving Hayabusa2 trajectory by combining LIDAR data and a shape model (2020)
  • Author(s): Matsumoto, K., Noda, H., Ishihara, Y., Senshu, H., Yamamoto, K., Hirata, N., Hirata, N., Namiki, N., Otsubo, T., Higuchi, A., Watanabe, S., Ikeda, H., Mizuno, T., Yamada, R., Araki, H., Abe, S., Yoshida, F., Sasaki, S., et al
  • Journal Title: Icarus Volume: 338 Pages: 113574-113574
  • DOI: 10.1016/j.icarus.2019.113574
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Space Weathering Simulation with Low-energy Laser Irradiation of Murchison CM Chondrite for Reproducing Micrometeoroid Bombardments on C-type Asteroids (2020)
  • Author(s): Matsuoka Moe、Nakamura Tomoki、Hiroi Takahiro、Okumura Satoshi、Sasaki Sho
  • Journal Title: The Astrophysical Journal Volume: 890 Issue: 2 Pages: L23-L23
  • DOI: 10.3847/2041-8213/ab72a4
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Density distribution of asteroid 25143 Itokawa based on smooth terrain shape (2019)
  • Author(s): Kanamaru Masanori、Sasaki Sho、Wieczorek Mark
  • Journal Title: Planetary and Space Science Volume: 174 Pages: 32-42
  • DOI: 10.1016/j.pss.2019.05.002
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Q-type asteroids: Possibility of non-fresh weathered surfaces (2019)
  • Author(s): Hasegawa, S., Hiroi, T., Ohtsuka, K., Ishiguro, M., Kuroda, D., Ito, T., Sasaki, S.
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 71 Issue: 5 Pages: 103-103
  • DOI: 10.1093/pasj/psz088
  • 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
• [Presentation] Sulfur effect of space weathering experiment simulating micrometeorite bombardment on the Hermean surface (2022)
  • Author(s): Sho Sasaki
  • Organizer: Workshop on Mercury’s Surface Response to the Interplanetary Environment
  • Int'l Joint Research
• [Presentation] Crack Orientation of Boulders on Ryugu: Meridional Preference and Exfoliation (2022)
  • Author(s): Sho Sasaki
  • Organizer: The 33rd ISTS (International Symposium on Space Technology and Science)
  • Int'l Joint Research
• [Presentation] Thermally Controlled Crack Orientation of Boulders on Ryugu: N-S Preference and Exfoliation Structure (2021)
  • Author(s): Sho Sasaki
  • Organizer: JpGU (Japan Geoscience Union) 2021
  • Int'l Joint Research
• [Presentation] リュウグウ表面の熱疲労 (2021)
  • Author(s): 佐々木晶
  • Organizer: 日本惑星科学会2021年秋季講演会
• [Presentation] 金属の露出した小惑星における 宇宙風化作用について (2021)
  • Author(s): 川上結生
  • Organizer: 日本惑星科学会2021年秋季講演会
• [Presentation] カンラン石への紫外光照射を用いた宇宙風化模擬実験 (2021)
  • Author(s): 盛満眞一
  • Organizer: 日本惑星科学会2021年秋季講演会
• [Presentation] Density Distribution within Small Solar System Bodies Based on Smooth Terrain Shape: Asteroid 25143 Itokawa and Comet 67P/Churyumov-Gerasimenko (2019)
  • Author(s): Kanamaru Masanori, Sasaki Sho, Wieczorek Mark
  • Organizer: Japan Geoscience Union 2019 assembly
  • Int'l Joint Research
• [Presentation] Brightness and morphology variations on surface boulders of 162173 Ryugu: Space weathering, breccia, and thermal cracks (2019)
  • Author(s): Sasaki Sho, Sugita Seiji, et al
  • Organizer: Japan Geoscience Union 2019 assembly
  • Int'l Joint Research
• [Presentation] Brightness and Morphology Variations on Surface Rocks of 162173 Ryugu by Hayabusa2: Space Weathering, Impacts, and Meridional Cracks (2019)
  • Author(s): Sasaki Sho, Sugita Seiji, Tatsumi Eri, et al
  • Organizer: EPSC-DPS2019
  • Int'l Joint Research
• [Presentation] 162173リュウグウ表面の高解像度画像から探る岩塊の熱疲労 (2019)
  • Author(s): 佐々木晶, 神田志穂ほか
  • Organizer: 日本惑星科学会2019年秋季講演会
• [Presentation] 月の表面を模擬した混合物組成による宇宙風化実験 (2019)
  • Author(s): 島名亮太、佐々木晶、廣井孝弘
  • Organizer: 日本惑星科学会2019年秋季講演会
• [Presentation] Cracks of Boulders on Ryugu: Possibility of Thermally-Induced Origin (2019)
  • Author(s): Sho Sasaki, Shiho Kanda, Hiroshi Kikuchi, et al
  • Organizer: Asteroid Science in the Age of Hayabusa2 and OSIRIS-REx
  • Int'l Joint Research
• [Presentation] Asteroid (162173) Ryugu by Hayabusa2 (2019)
  • Author(s): Sho Sasaki
  • Organizer: 第20回惑星圏研究会
  • Invited
• [Presentation] Brightness ans Morphology Variations on Surface rocks of 162173 Ryugu: Space Weathering, Breccia Structure and Meridional Cracks (2019)
  • Author(s): Sho Sasaki
  • Organizer: The 50th Lunar and Planetary Science Conference
  • Int'l Joint Research
• [Presentation] Sulfur-Powered Space Weathering (2018)
  • Author(s): Sho Sasaki
  • Organizer: Japan Geoscience Union 2018 assembly
  • Int'l Joint Research
• [Presentation] Promotion of Space Weathering with Sulfur (2018)
  • Author(s): Sho Sasaki
  • Organizer: COSPAR General Assembly
  • Int'l Joint Research
• [Presentation] 162173 リュウグウの表面の明るさと色の変化：宇宙風化、熱疲労、物質移動 (2018)
  • Author(s): 佐々木晶
  • Organizer: 日本惑星科学会2018年秋季講演会
• [Presentation] 硫黄に富んだ環境下での宇宙風化の模擬実験と分光計測 (2018)
  • Author(s): 田中宏和
  • Organizer: 日本惑星科学会2018年秋季講演会
• [Presentation] Brightness and Color Variations on the Surface of 162173 Ryugu: Space Weathering, Thermal Fatigue and Mass Movement (2018)
  • Author(s): Sho Sasaki
  • Organizer: American Geophysical Union 2018 Fall Meeting
  • Int'l Joint Research
• [Book] 太陽・惑星系と地球 (2019)
  • Author(s): 佐々木 晶、土`山 明、笠羽 康正、大竹 真紀子
  • Total Pages: 400
  • Publisher: 共立出版
  • ISBN: 9784320047099