37th DPS Meeting, 4-9 September 2005
Session 56 TNOs and Centaurs
Poster, Thursday, September 8, 2005, 6:00-7:15pm, Music Recital Room

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[56.04] Thermal Structure of Centaur Objects

Y. J. Choi (Jet Propulsion Laboratory), D. Prialnik, N. Brosch (Tel Aviv University)

The Centaur objects are a peculiar population among the small bodies in our Solar System, showing a wide range of color and various degrees of surface activity. The fundamental causes believed to induce global or local changes on the surfaces of these bodies, when the objects have a common origin in the Kuiper belt, are thermal evolution by insolation with or without radiogenic heating, and collisions among the same objects. The incident solar energy on the surface of Centaurs is sensitive to a number of parameters: the semi-major axis, the eccentricity of the orbit, and the rotation state (period, obliquity) of the specific object. We calculated thermal models for the orbital (a-e) space of Centaurs, assuming an initial composition consisting of amorphous ice with various trapped volatiles. We found in some orbits, instances of strong outbursts driven by a double-crystallization mechanism; these may explain observed Centaur outbursts at post-perihelion distanceS. Outgassing, by sublimation of icy volatiles that subsequently recondense, could contribute color changes to the surface.

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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.