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Crystallization of amorphous ice as the cause of Comet P/Halley's outburst at 14 AUAn explanation is provided for the postperihelion eruption of Comet P/Halley, detected in February 1991 and believed to have started three months earlier, namely, the crystallization of amorphous ice taking place in the interior of the porous nucleus, at depths of a few tens of meters, accompanied by the release of trapped gases. Numerical calculations show that for a bulk density of 0.5 g/cu cm and a pore size of 1 micron crystallization occurs on the outbound leg of Comet P/Halley's orbit, at heliocentric distances between 5 AU and 17 AU. The trapped gas is released and flows to the surface through the porous medium. It may also open wider channels, as the internal pressures obtained surpass the tensile strength of cometary ice. The outflowing gas carries with it grains of ice and dust, and thus can explain the large amounts of dust observed in the coma at 14.3 AU and beyond.
Document ID
19930059157
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Prialnik, D.
(NASA Headquarters Washington, DC United States)
Bar-Nun, A.
(Tel Aviv Univ. Israel)
Date Acquired
August 16, 2013
Publication Date
May 1, 1992
Publication Information
Publication: Astronomy and Astrophysics
Volume: 258
Issue: 2
ISSN: 0004-6361
Subject Category
Astrophysics
Accession Number
93A43154
Distribution Limits
Public
Copyright
Other

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