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A probability of encounter with interstellar comets and the likelihood of their existenceA theory of the probability of encounter of the sun with an interstellar comet at a distance comparable to the earth-sun distance is formulated, and a general expression is derived establishing the relationship among the influx rate of interstellar comets, the perihelion distance, the space density of the comets, the Maxwellian distribution of comet velocities in the interstellar cloud, and the cloud's systematic velocity relative to the sun. An upper limit of .0006 solar mass per cubic parsec is established for the space density of interstellar comets. The theoretical distribution of semimajor axes of interstellar comets shows that a strong hyperbolic excess must be present in the orbits of a majority of interstellar comets regardless of the dynamical characteristics of the comet cloud, except when the cloud is moving along with the sun and the distribution of individual velocities has a very low dispersion. This case, however, implies a possibility of capture by the sun and thus becomes a problem of an Oort-type cloud.
Document ID
19760041719
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Sekanina, Z.
(Harvard College Observatory and Smithsonian Astrophysical Observatory Cambridge, Mass., United States)
Date Acquired
August 8, 2013
Publication Date
January 1, 1976
Publication Information
Publication: Icarus
Volume: 27
Subject Category
Astrophysics
Accession Number
76A24685
Funding Number(s)
CONTRACT_GRANT: NSG-7082
Distribution Limits
Public
Copyright
Other

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