Home > Articles > Published articles > Nanoindenting the Chelyabinsk meteorite to learn about impact deflection effects in asteroids |
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 |
Postprint 30 p, 1.5 MB |