In-situ observation of catastrophic disruption of asteroid analogues using flash X-ray photography and its implication for the collisional evolution of size frequency distribution of asteroids
| Project/Area Number |
16H04041
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Solid earth and planetary physics
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| Research Institution | Kobe University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
大槻 圭史 神戸大学, 理学研究科, 教授 (00250910)
長澤 真樹子 久留米大学, 医学部, 教授 (00419847)
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| Research Collaborator |
Jutzi Martin
YASUI minami
OKAZAKI masashi
NAKAMURA masato
NAGANO takumi
SUETSUGU ryo
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥18,330,000 (Direct Cost: ¥14,100,000、Indirect Cost: ¥4,230,000)
Fiscal Year 2018: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2017: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Fiscal Year 2016: ¥11,830,000 (Direct Cost: ¥9,100,000、Indirect Cost: ¥2,730,000)
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| Keywords | 衝突破壊強度 / 小惑星 / フラッシュX線 / 脱出速度 / 重力支配域 / 再集積天体 / 多孔質天体 / 空隙率 / 引っ張り強度 / 衝突再集積 / フラッシュＸ線 / 小惑星サイズ頻度分布 / 微惑星 / 物質強度 / 内部摩擦 / 粘性 / 衝突破片速度分布 / サイズ頻度分布 / カタストロフック破壊 / 二段式軽ガス銃 / 惑星形成・進化 / 固体惑星・衛星・小惑星 / 惑星探査 |
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| Outline of Final Research Achievements |
High-velocity impact experiments were conducted for asteroid analogues to study the impact strength in a gravity regime. The catastrophic disruption of asteroid analogues with different tensile strength and porosities were observed by using flash X-ray photography, and the relationship between the impact fragment mass and the ejection velocity was obtained. The median velocity, V*, which is an upper limit of ejection velocities of fragments with a half of the original target mass was derived from this relationship and it was found to increase lineally with the energy density but it was independent of the tensile strength. While the V* was drastically affected by the porosity, the V* of the non-porous target was more than 3 time larger than that of the porous targets. These V* of various targets allowed us to estimate the impact strength of asteroid analogues in the gravity regime.
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| Academic Significance and Societal Importance of the Research Achievements |
数値計算と室内実験を比較・検討することで理論モデルの妥当性を評価することが可能となり、今回求めた「重力支配域の衝突破壊強度」は、従来得られていた原始惑星形成時間や惑星への衝突天体サイズ、小天体の衝突破壊進化過程に影響を与え、これらの見直しを迫る結果である。さらに、重力支配域の天体衝突において衝突破壊強度の構成物質依存性が明らかになったので、微惑星（数km）から準惑星（1000km）への衝突集積モデルの再検討が可能となった。また、小惑星帯には構成物質が異なる複数タイプの小惑星が存在することが知られているが、今回の結果からタイプ毎の小惑星のサイズ頻度分布について新しい仮説の提案が可能となった。
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Report
(4 results)
Research Products
(36 results)
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[Journal Article] Performance of Hayabusa2 DCAM3-D camera for short-range imaging of SCI and ejecta curtain generated from the artificial impact crater formed on asteroid 162137 Ryugu (1999 JU3)2016
Author(s)
Arakawa, M.;Wada, K.;Saiki, T.;Kadono, T.;Takagi, Y.;Shirai, K.;Okamoto, C.;Yano, H.;Hayakawa, M.;Nakazawa, S.;Hirata, N.;Kobayashi, M.;Michel, P.;Jutzi, M.;Imamura, H.;Ogawa, K.;Sakatani, N.;Iijima, Y.;Honda, R.;Ishibashi, K.;Hayakawa, H.;Sawada, H.
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Journal Title
Space Science Review
Volume: -
Issue: 1-4
Pages: 1-26
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Presentation] Impact experiments on porous gypsum and glass simulating rocky planetesimals and proto planets: Collisional properties in oblique impacts2018
Author(s)
Yasui, M., Arakawa, M., Yoshida, Y., Matsue, K., Takano, S., and Ogawa, K.
Organizer
9th Workshop on Catastrophic Disruption in the Solar System
Related Report
Int'l Joint Research
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[Presentation] Thermal conductivity model for powdered materials under vacuum based on experimental studies2017
Author(s)
Sakatani, N., Ogawa, K., Iijima, Y., Arakawa, M., Honda, R., and Tanaka, S.
Organizer
48th Lunar and Planetary Science Conference
Place of Presentation
The Woodlands (Texas, U.S.A.)
Year and Date
2017-03-20
Related Report
Int'l Joint Research
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[Presentation] Effect of oblique impact on impact strength of planetesimals2016
Author(s)
Yasui, M., Yoshida, Y., Matsue, K., Takano, S., Arakawa, M., Ogawa, K., and Okamoto, C.
Organizer
DPS 48/EPSC 11 Meeting
Place of Presentation
Pasadena ( CA, U.S.A.)
Year and Date
2016-10-16
Related Report
Int'l Joint Research
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