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The Diversity of Carbon in Cometary Refractory Dust ParticlesWhen comparing the dark icy surfaces of outer solar system small bodies and the composition of carbonaceous chondrites derived from dark asteroids we find a significant discrepancy in the assessed amounts of elemental carbon: up to 80% amorphous carbon is used to model the dark surfaces of Kuiper Belt Objects and Centaurs whereas at most 5% of elemental carbon is found in carbonaceous chondrites. If we presume that regimes of comet nuclei formation are analogous to disk regimes where other outer solar system ice-rich bodies formed then we can turn to comet dust to gain insights into the diversity in the concentration and forms of carbon available in the outer disk. Comet dust offers important insights into the diversity in the amounts and forms of carbon that were incorporated into aggregate dust particles in the colder parts of the protoplanetary disk out of which comet nuclei accreted. Comet nuclei are amongst the most primitive bodies because they have remained cold and unequilibrated. Comet dust particles reveal the presence of forms of elemental carbon and of soluble and insoluble organic matter, and in a great diversity of concentrations from very little, e.g., Stardust samples of comet 81P/Wild 2, to 80% by volume for Ultra Carbonaceous Antarctic Micro Meteorites (UCAMMs). Cometary outbursts and/or jet activity also demonstrate variations in the concentration of carbon in the grains at different grain sizes within a single comet. We review the diversity of carbon-bearing dust grains in cometary samples, flyby measurements and deduced from remote-sensing to enrich the discussion about the diversity of carbonaceous matter available in the outer ice-rich disk at the time of comet nuclei formation.
Document ID
20180002130
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Wooden, D. H.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
March 28, 2018
Publication Date
April 25, 2018
Subject Category
Astronomy
Report/Patent Number
ARC-E-DAA-TN53869
Meeting Information
Meeting: Carbon in the Solar System Workshop
Location: Denver, CO
Country: United States
Start Date: April 25, 2018
End Date: April 27, 2018
Sponsors: NASA Headquarters
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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