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Gas and dust emission from comets and life spans of active areas on their rotating nucleiOutgassing and dust emission from discrete regions on the nuclei of comets are investigated with regard to the processes of activation, dormancy, reactivation, and extinction. With regard to P/Halley, P/Encke, P/Tempel 2, P/Machholz, P/Takamizawa, Bowell and some other new comets, the evolution of one active region of the nucleus surface appears to be independent of the evolution of another active region. The traditional concept of deactivation as a slow and monolithic process needs to be replaced with a more dynamic concept of intermittent periods of dormancy and reactivation of individual vents, varying in size. Life spans of discrete sources of activity are estimated to be at a few hundred revolutions about the sun for comets with perihelia at heliocentric distances of less than 2 AU, if the bulk density is very low.
Document ID
19900066045
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Sekanina, Z.
(JPL Pasadena, CA, United States)
Date Acquired
August 14, 2013
Publication Date
October 1, 1990
Publication Information
Publication: Astronomical Journal
Volume: 100
ISSN: 0004-6256
Subject Category
Astrophysics
Accession Number
90A53100
Distribution Limits
Public
Copyright
Other

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