Properties of Original Impactors Estimated from Three-Dimensional Analysis of Whole Stardust Tracks

TL;DR

This study uses advanced 3D imaging and X-ray fluorescence to analyze Stardust cometary tracks, providing new methods for estimating impactor properties and reconstructing original particle characteristics.

Contribution

It introduces a novel methodology combining 3D imaging and X-ray fluorescence for non-destructive analysis of impactors in aerogel tracks.

Findings

Measured track volumes and entry hole sizes.

Demonstrated a method for estimating impactor ablation rates.

Outlined a framework for reconstructing original impactor size.

Abstract

The Stardust mission captured comet Wild 2 particles in aerogel at 6.1 km/sec. We performed high resolution three-dimensional imaging and X-ray fluorescence mapping of whole cometary tracks in aerogel. We present the results of a survey of track structures using Laser Scanning Confocal Microscopy, including measurements of track volumes, entry hole size and cross-sectional profiles. We compare various methods for measuring track parameters. We demonstrate a methodology for discerning hypervelocity particle ablation rates using synchrotron-based X-ray fluorescence, combined with mass and volume estimates of original impactors derived from measured track properties. Finally, we present a rough framework for reconstruction of original impactor size, and volume of volatilized material, using our measured parameters. The bulk of this work is in direct support of non-destructive analysis and identification of cometary grains in whole tracks, and its eventual application to the reconstruction of the size, shape, porosity and chemical composition of whole Stardust impactors.