Comet Formation and Evolution

Abstract

In this chapter the authors review the status of the hypotheses for comet formation and evolution as they were perceived before the spacecraft missions to Halley's comet. Since the missions gave the first observations of a nucleus, it is easily understood that the images of the nucleus will have the largest impact on modifying these hypotheses. Also a much more detailed composition of the frozen gases in the nucleus could be determined than was possible from ground-based observations and the dust size distribution and composition brought totally unexpected results. Thus the P/Halley data provide new constraints for the hypotheses of comet origin and evolution. Contents: Introduction. Chemical and physical clues from observations. Formation of comet nuclei. Dynamical evolution of comets. Physical evolution of comet nuclei. Summary.