DPS 34th Meeting, October 2002
Session 17. Centaurs and Kuiper Belt
Poster, Chair(s): , Tuesday, October 8, 2002, 3:30-6:00pm, Exhibit Hall

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[17.08] Could Collisions be the cause of the color diversity in the Kuiper Belt? A numerical test

A. Doressoundiram, Ph. Thébault (Observatoire de Paris)

The Collisional Resurfacing scenario supposes that mutual collisions among KBOs regularly excavate fresh neutral material to the objects surface and might counteract the competing space weathering reddening process. While the reddening process should act relatively homogeneously throughout the belt, the collision-induced bluishing should depend on the KBOs excitations and locations. The problem addressed by the present study is whether or not such inhomogeneities in collision rates and intensities could account for the observed inhomogeneities in color indexes within the belt. We perform deterministic numerical simulations in order to obtain (e,a) and (i,a) maps of the anisotropies in the relative total amount of kinetic energy, \Sigma Ci, received by collisions by KBOs. We consider a population of target objects embedded in a larger swarm of smaller impactors with which they collisionally interact. 4 different impactor disks have been considered. Results show a general correlation between high \Sigma Ci and high orbital excitation which resembles the equivalent correlation for bluer objects in the ``real'' KB. Another important feature is a significant correlation between high \Sigma Ci and low perihelion q values, which resembles again the observed correlation between bluer KBOs and low q. Nevertheless, significant departures from the observed spatial distribution of bluer KBOs are also obtained: 1) there is a significant tendency towards high \Sigma Ci plutinos whereas no tendency towards bluer plutinos is observed in the ``real'' belt. 2) there is a much better correlation with e than with i, whereas the opposite feature is observed in the real belt. Whether these contradictions invalidate the whole CR scenario or not remains yet uncertain, since the physical processes at play are still far from being fully understood and the sample of available observational data is still relatively limited. But it seems nevertheless that the scenario might not hold in its simple present form.

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Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.