In-Situ Observations of The Interplanetary Dust Population From Earth To The Edgeworth-Kuiper Belt

Piquette, Marcus Ryan

Graduate Thesis Or Dissertation

In-Situ Observations of The Interplanetary Dust Population From Earth To The Edgeworth-Kuiper Belt Public Deposited

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Citeable URL: https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/cv43nx64b

Abstract

Dust grains permeate the solar system due to the mutual collisions of asteroids, the break-up and outgassing of comets, and the mutual collisions and bombardment of bodies in the Edgeworth-Kuiper Belt (EKB). Characterizing the sources, sinks, and transport mechanisms of interplanetary dust particles (IDPs) provides constraints on fundamental processes that shape planetary systems. The Student Dust Counter (SDC) aboard the New Horizons spacecraft is the first calibrated dust detector to make in-situ measurements of IDPs from Earth all the way into the EKB. SDC is sensitive to grains larger than 10^-12 g providing constraints on the dust production, collisional history, bombardment environment, and distribution of bodies in the EKB. The spatial density of IDPs is nearly constant at 20 km^-3 from 15 AU to the EKB representing a 2-fold increase compared to densities interior of 10 AU. SDC measurements are consistent with observations from Cassini's Cosmic Dust Analyzer (CDA) at Saturn but consist of a much steeper power law index of mass distribution. Compared with Pioneer 10, SDC observations represents an intractable deficit of larger grains representing a factor of 1000 difference in dust flux. This disagreement brings into question both Pioneer 10's measurements and the ability of SDC to accurately measure the mass of impacting particles. In order to explore the accuracy of SDC's mass determination and commensurate SDC observations with Pioneer 10 and CDA we considered several solutions. Namely, we tested the robustness of the assumed impacts speeds used to estimate dust mass, the ability of dust grains to penetrate Polyvinylidene Flouride (PVDF) detectors, and the calibration of the PVDF in response to varying particle density and impact angle. Of these possibilities, none are shown to dramatically alter the mass determination of SDC data that is required to remain consistent with Pioneer 10 and CDA. If SDC's results are correct, the steep distribution of mass has important implications for the processes that govern the dynamics and evolution of bodies in the EKB. Particularly, the lifetimes and production of larger grains may be overestimated in current models bearing insight to the dominant dust production mechanism in the EKB.

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