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O.R. Hainaut, A.C. Delsanti (ESO/Chile), E. Jourdeuil (CRA Lyon)
In order to cast some light on the color distributions observed in Minor Bodies in the Outer Solar System, we have set up a simple numerical model simulating their surface evolution. At this stage, to represent the reddening of the surface, we use a series of empirical functions reproducing laboratory spectra of irradiated ices (Thompson, JGR 87). The collisions affecting the objects are modeled using the results of Stern (AJ 95). We also take into the cometary activity, with some very simple representation of the different species playing a role in the activity and of the mantling effect.
The model can be used in two ways: 1/ generate the evolution track of an object in a color-color diagram, and therefore illustrate the path of various objects depending which aging process dominates its surfaces, and 2/ to study the color distribution of a population as a whole. Currently, turning off the cometary activity, we obtain results very similar to those of Luu and Jewitt (AJ 96, 01). However, taking the ice sublimation into account, we obtain objects with a much more uniform color over their surface (which was one of the major problem of their model). We can also easily obtain very red and very blue Centaurs (like Pholus/Chiron). While the model is still extremely simple, it already gives some very encouraging results, which will be highlighted in this poster.
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Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.