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Radiation pressure — a stabilizing agent of dust clouds in comets?
Author(s) -
Fr$Ouhlich H.E.,
Notni P.
Publication year - 1988
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.2113090211
Subject(s) - radiation pressure , physics , cloud computing , radiation , dissipation , molecular cloud , astrophysics , particle (ecology) , dispersion (optics) , acceleration , range (aeronautics) , mechanics , computational physics , astronomy , optics , classical mechanics , materials science , stars , geology , computer science , thermodynamics , operating system , composite material , oceanography
The internal dynamics of an illuminated dust cloud of finite optical thickness is investigated. The dependence of the radiation pressure on the optical depth makes the individual particles oscillate, in one dimension, around the accelerated centre of gravity of the cloud. The cloud moves as an entity, irrespectively of the velocity dispersion of the particles and their efficiency for radiation pressure. If the optical depth does not change, i.e. if the cloud does not expand laterally, its lifetime is unlimited. A contraction caused by energy dissipation in mechanical collissions between the dust particles is expected. The range of particle sizes which can be transported by such a “coherent cloud” is estimated, as well as the acceleration of the whole cloud. The structure of the cloud in real space and in velocity space is investigated. A comparison with the “striae” observed in the dust tails of great comets shows that the parent clouds of these striae may have been of the kind considered.