Physics of the Shoemaker-Levy 9 Impacts

Dr. Joseph Harrington (Cornell)

With almost every major telescope and available spacecraft participating, the Shoemaker-Levy 9 impacts onto Jupiter were the most-observed events in the history of professional astronomy. Yet, there remain many more questions than answers surrounding the voluminous observations: Why were the debris patterns shaped as they were? How could the impact-site temperature drop many times faster than can be explained by thermal radiation? What caused the last of the precursor flashes in the lightcurves, and how about the post-impact flare or the oscillatory "bounces" observed at Palomar and elsewhere? Why did a ring of heat expand at more than 1.5 times the sound speed for hours after impact? Why did the lightcurves' shapes depend so strongly on wavelength? Only about 20 theoretical papers exist, all focussing on the early, data-scarce phases of the events. Almost none connect to data in a meaningful way. We have divided the impacts into phases based on the prevailing physics. Our new models extend early-phase theory to times when good observations are available, and create synthetic observables for detailed comparison to the data. Our models now explain all features of the images and lightcurves, introduce no new features, and reveal new insights into the physics of large impacts.

This talk will be given at the Cornell Astronomy Department Colloquium, 4:30 - 5:30 pm, Thursday 1 March 2000, in room 105 Space Sciences Building. Refreshments at 4:10.

Last revised: 2000 Nov 22 - J. Harrington