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Bills 1992
Bills, B.G. (1992). Venus: Satellite orbital decay, ephemeral ring formation, and subsequent crater production. Geophysical Research Letters 19: doi: 10.1029/92GL01067. issn: 0094-8276.

The remarkable state of preservation of Venus impact craters may reflect their recent origin from a circumplanetary source, rather than a recent decline in resurfacing efficiency. Many of the craters observed on Venus may have been produced by impacts of particles on tidally decaying, high inclination orbits about the planet, rather than asteroidal or cometary debris on heliocentric orbits. A single satellite with radius of 100--200 km, and initial orbital distance of 15--20 times the radius of Venus could have been the original source for all of the impacting material. Over a fairly wide range of initial conditions and tidal evolution models, the transfer of angular momentum from the satellite orbit to the planetary spin leads to a situation in which the satellite passes inside the Roche limit at high inclination to the equator of Venus. After the satellite is tidally disrupted, the fragments quickly spread out over the orbital path, and differential precession forms a partial shell of material. Subsequent collisional damping of relative inclinations collapses the particles into a flat ring, with one of three possible stable orientations; prograde equatorial, retrograde equatorial, or perpendicular to the equatorial plane. Rapid radial inflow accompanies collapse into either equatorial ring. Initial inclinations greater than 30¿ at the time of disruption will lead to impact onto the surface during ring formation. Fragmentation reaches a steady state when the largest remaining particles have radii of 10--20 km. Bilateral symmetry of ejecta patterns reflect grazing impacts.

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Abstract

Keywords
Planetology, Solid Surface Planets and Satellites, Cratering, Planetology, Solid Surface Planets and Satellites, Orbital and rotational dynamics, Planetology, Solid Surface Planets and Satellites, Rings and dust, Planetology, Solid Surface Planets and Satellites, Surfaces
Journal
Geophysical Research Letters
http://www.agu.org/journals/gl/
Publisher
American Geophysical Union
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