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Cosmic dust synthesis by accretion and coagulationThe morphology of grains grown by accretion and coagulation is revaled by a new laboratory method of synthesizing cosmic dust analogs. Submicron carbon particles, grown by accretion of carbon atoms from a gas, have a spherical shape with a cauliflower-like surface and an internal micro-structure of radial columns. This shape is probably common for grains grown by accretion at a temperature well below the melting point. Coagulated grains, consisting of spheres that collided to form irregular strings, were also synthesized. Another shape we produced had a bumpy non- spherical morphology, like an interplanetary particle collected in the terrestrial stratosphere. Besides these isolated grains, large spongy aggregates of nanometer-size particles were also found for various experimental conditions. Grains were synthesized using ions to sputter a solid target, producing an atomic vapor at a low temperature. The ions were provided by a plasma, which also provided electrostatic levitation of the grains during their growth. The temporal development of grain growth was studied by extinguishing the plasma after various intervals.
Document ID
19950049080
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Praburam, G.
(Univ. of Iowa, Iowa City, IA United States)
Goree, J.
(Univ. of Iowa, Iowa City, IA United States)
Date Acquired
August 16, 2013
Publication Date
March 10, 1995
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 441
Issue: 2
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A80679
Funding Number(s)
CONTRACT_GRANT: NAG8-292
CONTRACT_GRANT: NAGW-3126
CONTRACT_GRANT: NSF ECS-92-15882
Distribution Limits
Public
Copyright
Other

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