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Episodic aging and end states of comets

Show simple item record Sekanina, Zdenek 2014-12-12T00:01:07Z 2014-12-12T00:01:07Z 2008-08-10
dc.identifier.citation SPIE Instruments, Methods, and Missions for Astrobiology, San Diego, California, August 10-14, 2008 en_US
dc.identifier.clearanceno 08-2723
dc.description.abstract It is known that comets are aging very rapidly on cosmic scales, because they rapidly shed mass. The processes involved are (i) normal activity — sublimation of ices and expulsion of dust from discrete emission sources on and/or below the surface of a comet’s nucleus, and (ii) nuclear fragmentation. Both modes are episodic in nature, the latter includes major steps in the comet’s life cycle. The role and history of dynamical techniques used are described and results on mass losses due to sublimation and dust expulsion are reviewed. Studies of split comets, Holmes-like exploding comets, and cataclysmically fragmenting comets show that masses of 10 to 100 million tons are involved in the fragmentation process. This and other information is used to investigate the nature of comets’ episodic aging. Based on recent advances in understanding the surface morphology of cometary nuclei by close-up imaging, a possible mechanism for large-scale fragmentation events is proposed and shown to be consistent with evidence available from observations. Strongly flattened pancake-like shapes appear to be required for comet fragments by conceptual constraints. Possible end states are briefly examined. en_US
dc.description.sponsorship NASA/JPL en_US
dc.language.iso en_US en_US
dc.publisher Pasadena, CA : Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2008 en_US
dc.subject nucleus en_US
dc.subject fragmentation en_US
dc.title Episodic aging and end states of comets en_US
dc.type Preprint en_US

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