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9/3/15: SO/NOAO Joint Colloquium Series: David Jewitt, UCLA


Title: The Active Asteroids

We have discovered a new class of solar system body. These objects are asteroids (rocks formed inside the snowline) when judged by their orbits but comets (dirt-ice conglomerates formed outside the snowline) when judged by their appearance. Scientifically, the "active asteroids" (also called "main-belt comets") are interesting in several respects. Some are sublimation driven, just like classical comets from the Kuiper belt and Oort cloud. They reside in a region of the solar system from which the Earth likely acquired water and their study may elucidate the origin of the terrestrial planet volatiles. We have also observed, for the first time, an asteroid-asteroid impact, objects that are shedding mass and breaking up under rotational instability, and an object disintegrating by thermal fracture. These new observations reveal processes that were previously beyond the realm of observation, with ramifications for the survival of solid bodies and the production of dust and debris in the solar system.

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