Exploring the Possible Continuum Between Comets and Asteroids

There are many indicators that suggest that the differences between asteroids and comets may result from their evolution over several billion years, based on similar accretion processes in the primitive solar nebula rather than in fundamental differences in their accretional histories. Our goal is to review some of the various processes (e.g., headwind drag-induced radial drift, grain–grain collisional dynamics, thermal processing vs. accretion time, etc.) that would act to accrete or to modify the accreted materials as a function of the size of the object. We do not account for the migration of the giant planets on the populations of asteroids and comets as the consequences of the proposed mixing episodes would come much later. We will, however, discuss the potential implications of the formation of the terrestrial planets on the population of meteorite parent bodies in the inner solar system. These same processes do not seem to have been important in or beyond the giant planet region of the solar nebula.