Results From the Comet Giacobini-Zinner and Halley Campaigns

The spacecraft flybys of Comets Giacobini-Zinner and Halley were highly successful. They confirmed many untested theories and provided, additional clues to decide between competing models, but without leading to a clear preference. They also raised new questions. Based on the improved knowledge, research efforts will now be much better focused than was possible before the encounters. Moreover, we should be better equipped to interpret Earth-based (ground-based, air-borne, rocket-borne, and Earth satellite) observations.

The goals of the workshop are defined in terms of the results from spacecraft measurements and Earth-based observations of Comets Giacobini-Zinner and Halley, A summary is presented of the new knowledge about the nucleus, the .coma gas and dust, and the plasma. We realize that we must be extremely cautious when generalizing results from the Comet Giacobini-Zinner and Halley investigations to comets universally. The many surprises of the successful missions, the dangers inherent in generalizations to other comets, and the many still open and new questions are the reasons for the need of further spacecraft investigations. However, an unquestionably successful start has been made in expanding out knowledge about the physics and chemistry of comets and all the related implications, and the question about the similarities of and differences between comets can now be explored further.