Affordable Access

Publisher Website

Models of the structure and evolution of comet P/Wirtanen

Planetary and Space Science
Publication Date
DOI: 10.1016/0032-0633(96)00048-7


Abstract Model calculations are presented for the nucleus of comet P/Wirtanen, the main target of the upcoming Rosetta mission. A porous, spherical nucleus, made of ice and dust in equal mass fractions is considered, assuming a few percent of CO and CO 2 occluded in the amorphous ice. The main effects included in the code are: crystallization of amorphous ice and release of occluded gases, condensation, sublimation and (Knudsen) flow of gases through the pores, changing pore sizes, flow of dust grains of different radi. Evolution is followed through several orbits, for different initial parameter combinations. It is found that a stratified structure develops for the outer layer of the nucleus: a highly porous dust mantle, a denser layer of crystalline ice and dust below it, followed by layers of amorphous ice and dust including frozen CO 2, and deeper down, frozen CO. The production rate of H 2O varies strongly with heliocentric distance; at perihelion the calculated rate is very close to that inferred from observations. The CO production rate is maintained nearly constant throughout the orbit and that of CO 2 varies moderately. Outbursts are obtained for some models at large heliocentric distances.

There are no comments yet on this publication. Be the first to share your thoughts.