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Comet Showers

Published online by Cambridge University Press:  07 August 2017

Julio A. Fernández
Julio A. Fernández*
Affiliation:
Departamento de Astronomía, Facultad de Ciencias, Tristan Narvaja 1674, Montevideo 11200, Uruguay.

Abstract

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Variations in the influx rate of incoming Oort cloud comets, leading to the occurrence of comet showers, are reviewed with special emphasis on the dynamical processes that produce them. It is found that comet showers as intense as 10-100 times the background comet flux may occur at average intervals of several 107 years, being very close stellar passages at distances ≈ 104AU and, perhaps, penetrating encounters with intermediate-size molecular clouds the trigger mechanisms. Penetrating encounters with giant molecular clouds and stellar passages at distances of a few 103AU may trigger comet showers about 102 − 103 times more intense than the background comet flux at average intervals of a few 108 years. The impact cratering record on the Earth does not show any clear evidence of past comet showers. Some orbital properties of new and dynamically young comets suggest that the influx rate of Oort cloud comets is currently near its background level.

Type
Part V - Comets
Information
Symposium - International Astronomical Union , Volume 152: Chaos, Resonance and Collective Dynamical Phenomena in the Solar System , 1992 , pp. 239 - 254
Copyright
Copyright © Kluwer 1992 

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