Comet Shoemaker-Levy 9: No effect on the Io plasma torus

Observations of the Io plasma torus made before, during, and after the impact of Comet Shoemaker-Levy 9 with Jupiter reveal no comet-induced changes. Three weeks of high spectral-resolution ground-based visible spectroscopy show no changes larger than typical day-to-day variations in the torus densities, ion temperatures, or rotation velocities. Comparison with six months of identically obtained data from 1991 and 1992 also shows no differences.