36th DPS Meeting, 8-12 November 2004
Session 3 Kuiper Belt I: Observations
Oral, Monday, November 8, 2004, 10:30am-12:noon, Clark

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[3.07] The Color of the Kuiper-Belt Core

A. A. S. Gulbis, J. L. Elliot, J. F. Kane (MIT)

The Kuiper belt is thought to be the least thermally modified region in the Solar System and thus provides unique insight into its formation and evolution. Subsets of Kuiper belt objects (KBOs) can be distinguished by correlations between dynamical characteristics and physical properties. This may lead to the identification of a grouping of objects that have undergone minimal processing and are representative of primitive material. Using recent results from the Deep Ecliptic Survey (DES), in which the plane of the Kuiper belt has been calculated (see the abstract by Elliot et al.), we search for correlations between KBO dynamical properties and colors. As a function of inclination with respect to the Kuiper-belt plane, there are distinct ``core" and ``halo" populations -- similar to the hot and cold populations proposed by others (e.g. Brown Astron. J. 121, 2804, 2001; Levison & Stern Astron. J. 121, 1730, 2001). The core objects are represented by a strong peak in object poles located within a few degrees of the pole of the Kuiper-belt plane, while the halo objects have a shallower distribution extending to inclinations beyond 30o. We use previously published data, along with new observations from the 6.5-m Clay telescope at Las Campanas Observatory, to investigate the colors of the core KBOs. We find that non-resonant objects having inclinations less than approximately 1.2o from the Kuiper-belt plane are distinctly redder than the general population. Correlations between color and perihelion distance, and color and inclination for ``Classical" KBOs, have been previously noted (e.g. Tegler et al. Astrophys. J. 599, L49, 2003; Trujillo & Brown Astrophys. J. 566, L125, 2002). However, the core sample contains ``Scattered" objects with low perihelion distances (q < 40) and high eccentricities. Funding for this research is provided by NASA Grant NAG04GF25G and NSF Grant AST-0073447.

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Bulletin of the American Astronomical Society, 36 #4
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