Extent of thermal ablation suffered by model organic microparticles during aerogel capture at hypervelocities

Burchell, Mark J., Foster, Nicholas J., Ormond-Prout, J, Dupin, D, Armes, Steven P. (2009) Extent of thermal ablation suffered by model organic microparticles during aerogel capture at hypervelocities. Meteoritics & Planetary Science, 44 (10). pp. 1407-1419. ISSN 1086-9379. (doi:10.1111/j.1945-5100.2009.tb01182.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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http://dx.doi.org/10.1111/j.1945-5100.2009.tb01182...

Abstract

New model organic microparticles are used to assess the thermal ablation that occurs during aerogel capture at speeds from 1 to 6 km s(-1). Commercial polystyrene particles (20 mu m diameter) were coated with all ultrathin 20 nm overlayer of an organic conducting polymer, polypyrrole. This overlayer comprises only 0.8% by mass of the projectile but has a very strong Raman signature, hence its survival or destruction is a sensitive measure of the extent of chemical degradation suffered. After aerogel capture, microparticles were located via optical microscopy and their composition was analyzed in situ using Raman microscopy. The ultrathin polypyrrole overlayer survived essentially intact for impacts at similar to 1 km s(-1), but significant surface carbonization was found at 2 km s(-1), and major particle mass loss at >= 3 km s(-1). Particles impacting at similar to 6.1 km s(-1) (the speed at which cometary dust was collected in the NASA Stardust mission) were reduced to approximately half their original diameter during aerogel capture (i.e., a mass loss of 84%). Thus significant thermal ablation occurs at speeds above a few km s(-1). This suggests that during the Stardust mission the thermal history of the terminal dust grains during capture in aerogel may be sufficient to cause significant processing or loss of organic materials. Further, while Raman D and G hands of carbon can be obtained from captured grains, they may well reflect the thermal processing during capture rather than the pre-impact particle's thermal history.

Item Type: Article
DOI/Identification number: 10.1111/j.1945-5100.2009.tb01182.x
Uncontrolled keywords: COATED POLYSTYRENE LATEXES; ENHANCED RAMAN-SCATTERING; COMET 81P/WILD-2; SURFACE CHARACTERIZATION; STARDUST SPACECRAFT; POLYPYRROLE; PARTICLES; IMPACTS; PROJECTILES; COLLECTION
Subjects: Q Science > QB Astronomy
Q Science > QD Chemistry
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: 06 Dec 2013 15:50 UTC
Last Modified: 29 May 2019 11:35 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/37249 (The current URI for this page, for reference purposes)
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