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A. Delsanti (Observatoire de Paris-Meudon), O. R. Hainaut (ESO/Chile), E. Jourdeuil (CRA/Lyon)
Kuiper Belt Objects display a broad distribution of colors, ranging from neutral (solar) to very red over the visible wavelength range. The hypothesis of different intrinsic compositions to explain such a diversity cannot be ruled out yet, but seems very unlikely given the small equilibrium temperature gradient across the belt (of the order of 10K). Another possibility is that the observed color distribution is the result of the competition between different resurfacing processes.
We revisited the model by Luu and Jewitt (1996), that considers a reddening by irradiation of the surface by high energy particles bombardment plus non-disruptive collisions between members of the Kuiper Belt. For collisions, we used the impact rates from Stern (1995). For the first time, we considered as an additional rejuvenating process a simple representation of cometary activity (i.e. volatile sublimation) that is very efficient at resurfacing objects in a uniform way, by redeposition of fresh -neutral colored- dust. This model allow us to produce much more uniform surfaces than when only considering the reddening and collisions processes and the observed color distribution is well reproduced. Moreover, this model has the advantage of reproducing and/or predicting the color behaviour of objects over a very wide range of heliocentric distances (from Short Period Comets to extremely distant objects)
We will describe the different aspects of the model, and detail the various results and predictions.
The author(s) of this abstract have provided an email address for comments about the abstract: Audrey.Delsanti@obspm.fr
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.