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Microstructure modifications of silicates induced by the collection in aerogel: Experimental approach and comparison with Stardust results

Stodolna, Julien, Jacob, Damien, Leroux, Hugues, Burchell, Mark J. (2012) Microstructure modifications of silicates induced by the collection in aerogel: Experimental approach and comparison with Stardust results. Meteoritics & Planetary Science, 47 (4). pp. 696-707. ISSN 1086-9379. (doi:10.1111/j.1945-5100.2011.01305.x) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1111/j.1945-5100.2011.01305.x

Abstract

Particles from comet 81P/Wild 2 were captured with silica aerogel during the flyby Stardust mission. A significant part of the collection was damaged during the impact at hypervelocity in the aerogel. In this study, we conducted impact experiments into aerogel of olivine and pyroxene powder using a light-gas gun in similar conditions as that of the comet Wild 2 particles collection. The shot samples were investigated using transmission electron microscopy to characterize their microstructure. Both olivine and pyroxene samples show evidence of thermal alteration due to friction with the aerogel. All the grains have rounded edges after collection, whereas their shape was angular in the initial shot powder set. This is probably associated with mass loss of particles. The rims of the grains are clearly melted and mixed with aerogel. The core of olivine grains is fairly well preserved, but some grains contain dislocations in glide configuration. We interpret these dislocations as generated by the thermal stresses that have emerged due to the high temperature gradients between the core and the rim of the grains. Most of the pyroxene grains have been fully melted. Their high silica concentration reflects a strong impregnation with melted aerogel. The preferential melting of pyroxene compared with olivine is due to a difference in melting temperatures of 300°. This melting point difference probably induces a bias in the measurements of the ratio olivine/pyroxene in the Wild 2 comet. The proportion of pyroxene was probably higher on Wild 2 than expected from the samples collected into aerogel.

Item Type: Article
DOI/Identification number: 10.1111/j.1945-5100.2011.01305.x
Subjects: Q Science > QB Astronomy
Q Science > QE Geology
Divisions: Faculties > Sciences > School of Physical Sciences
Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: Mark Burchell
Date Deposited: 11 Nov 2013 15:09 UTC
Last Modified: 01 Aug 2019 10:36 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/36168 (The current URI for this page, for reference purposes)
Burchell, Mark J.: https://orcid.org/0000-0002-2680-8943
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