Paper: astro-ph/0504653
Date: Fri, 29 Apr 2005 01:59:54 GMT (10kb)

Title: Solving the mystery of Iapetus

Authors: Paulo C. C. Freire
Comments: Submitted to Journal of Geophysical Research - Planets
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Since the discovery of Iapetus by G. D. Cassini, in 1672, it has been known
that the leading hemisphere of this Saturnian satellite is one order of
magnitude darker than the trailing hemisphere. Since the Cassini spacecraft
entered the Saturnian orbit, several high-quality images of the dark hemisphere
of Iapetus have been obtained, in particular during the Dec 31 2004 flyby of
this satellite. These images revealed the presence of a large equatorial ridge
in the dark hemisphere of Iapetus. We propose that this ridge and the dark
coating of the hemisphere on which it lies are intimately interlinked and are
the result of a collision with the edge of a primordial Saturnian ring,
ultimately caused by a sudden change in the orbit of Iapetus. The model
naturally explains all of the the unique features of this satellite; it is
probably the solution to one of the oldest mysteries in solar system astronomy.

\\ ( http://arXiv.org/abs/astro-ph/0504653 , 10kb)