C. R. Chapman
The Galileo spacecraft, unlike all near-Earth observatories, had a direct view of the Shoemaker-Levy 9 impact sites. The solid state imaging system thus was able to take the only direct pictures of the impact sites. As of this writing, very little data has been returned, but it is sufficient to say that we have detected events K and W. Event K lasted about 45 seconds and reached ~10% the brightness of Jupiter itself; W was visible for at least 5 seconds (that may be a lower bound) and reached 1% the brightness of Jupiter. The partial data returned from N is inconclusive.
By the end of October, we will have returned all of the data we plan to return from the spacecraft tape recorder for events N and K, as well as a very interesting portion of the W data set. Therefore, by the time of the AGU meeting, we should be able to characterize these luminous phenomena in terms of the important phases of the impact phenomenology -- bolide, fireball, plume, etc. By merging these data sets with other data (e.g. HST, ROSAT, groundbased, etc.), it should be possible to define many important characteristics of the impacts that would not be possible to infer solely from the groundbased data. For example, the total energy deposition, and its rate of deposition in Jupiter's atmosphere, can be constrained from Galileo data of prompt phenomena, and thus establish the "initial conditions" for the subsequent fireball, plume, and spot-creation processes that were so thoroughly studied from Earth.
This research has been made possible by special efforts on the part of the Galileo Project team, and especially by the hard work of Catherine Heffernan and Ken Klaasen, of J.P.L., who I thank on behalf of Mike Belton and the SSI Team.
Sept. 19, 1994.