Imperial College London
Portrait Picture

Professor Gareth Collins

Faculty of Engineering, Department of Earth Science & Engineering

Professor of Planetary Science
 
 
 
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Contact

 

+44 (0)20 7594 1518g.collins Website

 
 
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Location

 

4.83Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Ormö:2022:10.1016/j.epsl.2022.117713,
author = {Ormö, J and Raducan, SD and Jutzi, M and Herreros, MI and Luther, R and Collins, GS and Wünnemann, K and Mora-Rueda, M and Hamann, C},
doi = {10.1016/j.epsl.2022.117713},
journal = {Earth and Planetary Science Letters},
pages = {1--12},
title = {Boulder exhumation and segregation by impacts on rubble-pile asteroids},
url = {http://dx.doi.org/10.1016/j.epsl.2022.117713},
volume = {594},
year = {2022}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Small asteroids are often considered to be rubble-pile objects, and such asteroids may be the most likely type of Near Earth Objects (NEOs) to pose a threat to Earth. However, impact cratering on such bodies is complex and not yet understood. We perform three low-velocity (≈ 400 m/s) impact experiments in granular targets with and without projectile-size boulders. We conducted SPH simulations that closely reproduced the impact experiments.Our results suggest that cratering on heterogeneous targets displaces and ejects boulders, rather than fragmenting them, unless directly hit. We also see indications that as long as the energy required to disrupt the boulder is small compared to the kinetic energy of the impact, the disruption of boulders directly hit by the projectile may have minimal effect on the crater size.The presence of boulders within the target causes ejecta curtains with higher ejection angles compared to homogeneous targets. At the same time, there is a segregation of the fine ejecta from the boulders, resulting in boulders landing at larger distances than the surrounding fine grained material. However, boulders located in the target near the maximum extent of the expanding excavation cavity are merely exhumed and distributed radially around the crater rim, forming ring patterns similar to the ones observed on asteroids Itokawa, Ryugu and Bennu. Altogether, on rubble-pile asteroids this process will redistribute boulders and finer-grained material heterogeneously, both areally around the crater and vertically in the regolith. In the context of a kinetic impactor on a rubble-pile asteroid and the DART mission, our results indicate that the presence of boulders will reduce the momentum transfer compared to a homogeneous, fine-grained target.
AU  - Ormö,J
AU  - Raducan,SD
AU  - Jutzi,M
AU  - Herreros,MI
AU  - Luther,R
AU  - Collins,GS
AU  - Wünnemann,K
AU  - Mora-Rueda,M
AU  - Hamann,C
DO  - 10.1016/j.epsl.2022.117713
EP  - 12
PY  - 2022///
SN  - 0012-821X
SP  - 1
TI  - Boulder exhumation and segregation by impacts on rubble-pile asteroids
T2  - Earth and Planetary Science Letters
UR  - http://dx.doi.org/10.1016/j.epsl.2022.117713
UR  - https://www.sciencedirect.com/science/article/pii/S0012821X22003491?via%3Dihub
UR  - http://hdl.handle.net/10044/1/98490
VL  - 594
ER  -
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