New dust ring for Jupiter?

When fragments of Comet Shoemaker-Levy 9 crash into Jupiter next July, many of the resulting physical and chemical changes in the upper atmosphere may only persist for days or weeks. But the encounter might also create a new dust ring around the planet that could take eight to 10 years to form and could last for more than 1,000 years.

According to Mihaly Horanyi of the University of Colorado at Boulder, shoemaker-levy's escapades have provided two key sources od dust: the comet's breakup last July, when it fragmented into some 20-odd pieces near jupiter; and the freshly exposed chunks, which themsleves release additional grains along the comet's trajectory. Only dust grains between 1.5 and 2.5 micrometers in diameter can lose just enough energy and angular momentum during collisions with charged particles in Jupiter's magnetosphere to coalesce into a ring, Horanyi notes. He calculates that the breakup of Shoemaker-Levy may have generated enough such dust for a ring.

The proposed ring would form much farther from Jupiter than its only known dust ring, identified in 1979. Horanyi estimates that it would lie 4.5 Jupiter radii from the planet and extend out to six Jupiter radii. He says the ring might be too faint for an infrared telescope to detect, but a dust detector aboard the Galileo spacecraft, which arrives near jupiter in 1995, might find evidence of a budding dust ring.