Moon Interactions with Jupiter's Rings
Debris blasted off the satellite Amalthea in high-speed collisions with interplanetary meteoroids will start with slightly inclined orbits like that of Amalthea (yellow lines), forming a slender tube around the satellite trajectory. These orbital paths are not, however, stationary in space but instead wobble about Jupiter's equator like a giant hula-hoop, keeping the same tilt off the equator but continually changing their orientations at rates that differ slightly depending on orbital size and shape. (Two orbits are shown at top.) Thus within a few years of the impact that formed the debris tube, the tube smears out into a thin cylindrical shell at Amalthea's orbital distance (web of lines shown in bottom panel). When viewed from the side within the equatorial plane, this hoop appears to be a thin rectangle. As the particles move to the top of their paths around Jupiter and back down, they pause at their greatest heights off the equatorial plane. Since all the debris particles have the same orbital tilts, this pausing leads to a ring that is slightly denser at the edges than in the equatorial plane. Following the early stages of evolution shown here, the particles will eventually drift inwards as they absorb sunlight, and fill a flat washer-shaped disk.
Image Credit: Jim Houghton, Galileo Imaging Team, NASA