Nanoindenting the Chelyabinsk meteorite to learn about impact deflection effects in asteroids
Moyano-Cambero, Carles Eduard (Institut de Ciències de l'Espai)
Pellicer Vilà, Eva Maria (Universitat Autònoma de Barcelona. Departament de Física)
Trigo Rodríguez, Josep Maria (Institut de Ciències de l'Espai)
Williams, Iwan P. (Queen Mary University of London. School of Physics and Astronomy)
Blum, Jürgen (Technische Universität Braunschweig. Institut für Geophysik und extraterrestrische Physik)
Michel, Patrick (Université de Nice. Institut de géographie. Laboratoire Lagrange)
Küppers, Michael (European Space Agency)
Martínez-Jiménez, Marina (Institut de Ciències de l'Espai)
Lloro, Ivan (Institut de Ciències de l'Espai)
Sort Viñas, Jordi (Universitat Autònoma de Barcelona. Departament de Física)

Date:	2017
Abstract:	The Chelyabinsk meteorite is a highly shocked, low porosity, ordinary chondrite, probably similar to S- or Q-type asteroids. Therefore, nanoindentation experiments on this meteorite allow us to obtain key data to understand the physical properties of near-Earth asteroids (NEAs). Tests at different length scales provide information about the local mechanical properties of the minerals forming this meteorite: reduced Young's modulus, hardness, elastic recovery, and fracture toughness. Those tests are also useful to understand the potential to deflect threatening asteroids using a kinetic projectile. We found that the differences in mechanical properties between regions of the meteorite, which increase or reduce the efficiency of impacts, are not a result of compositional differences. A low mean particle size, attributed to repetitive shock, can increase hardness, while low porosity promotes a higher momentum multiplication. Momentum multiplication is the ratio between the change in momentum of a target due to an impact, and the momentum of the projectile, and therefore higher values imply more efficient impacts. In the Chelyabinsk meteorite the properties of the light-colored lithology materials facilitate obtaining higher momentum multiplication values, compared to the other regions described for this meteorite. Also, we found a low value of fracture toughness in the shock-melt veins of Chelyabinsk, which would promote the ejection of material after an impact and therefore increase the momentum multiplication. These results are relevant in the context of a future mission to test asteroid deflection, currently being studied by ESA and NASA: the Asteroid Impact and Deflection Assessment (AIDA) mission.
Grants:	Ministerio de Economía y Competitividad MAT2014-57960-C3-1-R Ministerio de Economía y Competitividad RYC-2012-10839 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-1015
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Meteorites ; Meteors ; Meteoroids ; Minor planets ; Asteroids: general
Published in:	The Astrophysical journal, Vol. 835, issue 2 (Feb. 2017) , art. 157, ISSN 1538-4357

DOI: 10.3847/1538-4357/835/2/157

Postprint 30 p, 1.5 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Group of Smart Nanoengineered Materials, Nanomechanics and Nanomagnetism (Gnm3)
Articles > Research articles
Articles > Published articles