Scientists from the University of Maryland and the Max-Planck Institute for Solar System Research in Germany appear to have solved a long-standing mystery about the cause of anomalies in Jupiter's gossamer rings.
In a new study published in the May 1 issue of Nature, they report that a faint extension of the outermost ring beyond the orbit of Jupiter's moon Thebe, and other observed deviations from an accepted model of ring formation, result from the interplay of shadow and sunlight on dust particles that make up the rings.
"It turns out that the outer ring's extended boundary and other oddities in Jupiter's rings really are 'made in the shade,'" said Douglas Hamilton, a professor of astronomy at the University of Maryland. " As they orbit about the planet, dust grains in the rings alternately discharge and charge when they pass through the planet's shadow. These systematic variations in dust particle electric charges interact with the planet's powerful magnetic field. As a result small dust particles are pushed beyond the expected ring outer boundary, and very small grains even change their inclination, or orbital orientation, to the planet."
Full article: http://www.sciencedaily.com/releases/2008/04/080430134305.htm
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