Comet Populations and Cometary Dynamics

Comets are small icy bodies regarded as remnants of the time of planetary accretion when the Solar System was formed. The chapter discusses where comets originated, where they have spent most of their lives, and how they occasionally evolve through the planetary system and move close enough to the Sun to become the spectacular objects we sometimes see in the night sky. The majority of observational information we have about these objects comes from the short phase when they are close to the Sun. The rest of the story is gleaned by combining this information with computer-generated dynamical models of the Solar System. A discussion of the behavior of the orbits of comets is presented along with a classification scheme for comets. Finally, the cometary reservoirs are described, which are believed to exist in the Solar System, today.