Meteoroid impact into short-period comet nuclei

Abstract

After their introduction into the inner Solar System, most short-period comets spend the majority of each orbit within the asteroid belt. Provided that cometary material is similar to terrestrial snow in its shock behaviour, the nuclei would accumulate meteoroids as a consequence of collisions with asteroidal debris. Here the effects which extended meteoroid bombardment might have on short-period comet nuclei in ideal conditions are evaluated; the results are extrapolated to more probable situations, and their possible implications for asteroid and meteorite studies are considered. It is suggested that after devolatilization of the nucleus, the accumulated material might combine with primary cometary solids to produce environments conducive to the formation of polymict brecciated meteorites and to influence reflectance spectra of the ‘asteroid’. In addition, such meteoroids removed from active nuclei during degassing could be placed in trajectories which might evolve into Earth-crossing orbits.