Large Dust Particles Around Cometary Nuclei

J. Knollenberg, E. Kührt (DLR)

The dynamics of large dust particles in the vicinity of rotating cometary nuclei is investigated using a computational model which includes effects of gas drag, nucleus gravity and inertia forces as well as tidal and radiation pressure forces. The drag force is provided by an axisymmetric continuum model of the gas flow field originating from an active region on the nucleus. It is shown that, dependent on the particle size distribution, up to some percent of the totally ejected dust mass could fall back onto the nucleus. The redistribution of particles on the nucleus surface and consequences for the mantle growth process are considered. Furthermore, a minor fraction of the dust could be launched in orbits around the comet. The results are discussed in the context of available observational evidence and possible implications concerning the ESA ROSETTA mission to comet P/Wirtanen.