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December 23, 2011
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Wild Stardust

Posted by John Jackson Dec 23, 2011

Samples returned from comet 81P/Wild 2 by the Stardust mission provided an unequalled opportunity to compare previously available extraterrestrial samples against those from a known comet. Iron sulphides are a major constituent of cometary grains commonly identified within cometary interplanetary dust particles (IDPs) and Wild 2 samples.  NHM scientists Sara Russell and Anton Kearsley, and Scientific Associate Phil Bland, are key collaborators on a new examination of this unique material.

 

Chemical analyses show that Wild 2 sulphides are fundamentally different from those in IDPs. However, as Wild 2 dust was collected via impact into capture media at approximately 6.1 km s-1, it is unclear whether this is due to original variations in these materials or is due to heating and alteration during collection. The results obtained are consistent with estimated peak pressures and temperatures experienced (approximately 85 GPa, approximately 2600 K) and some may be used to predict original chemistry and estimate mineralogy - the work continues....


Wozniakiewicz P J, Ishii H A, KEARSLEY A T, Burchell M J, BLAND P A, Bradley J P, Dai Z R,   Teslich N, Collins G S, Cole M J & RUSSELL S S 2011. Investigation of iron sulfide impact crater residues: A combined analysis by scanning and transmission electron microscopy. Meteoritics and Planetary Science 46: 1007-1024.