April 2014

DATE EVENT LOCATION
Monday, Apr 28
12:00 pm — 1:00 pm
Brown Bag Colloquium: Dr. Bashar Rizk
Dr. Bashar Rizk
OCAMS Instrument Scientist
University of Arizona - Lunar and Planetary Laboratory

Rounded Boulders on Itokawa and YORP Spin-up of Rocks in a Micro-gravity Environment
Abstract:
The observation that some boulders on Itokawa look rounded provides the impetus to suggest a mechanism, YORP - induced spin-up of smaller rock sizes to very high spin rates causing collision chain reactions, that would seem to be a very powerful one given the very weak cohesive environment of microgravity objects. Such rapid rotators, through their collisions, could also induce alterations in the YORP spin-up capabilities of other rocks due to changes in the radiative asymmetry. We present order-of-magnitude estimates of this effect, consider possible modes in which the system might develop, confront the main uncertainties and outline work to reduce the unknowns.
Kuiper Space Sciences: Room 309
Tuesday, Apr 29
3:45 pm
LPL Colloquium: Dr. Bashar Rizk
Dr. Bashar Rizk
OCAMS Instrument Scientist
University of Arizona - Lunar and Planetary Laboratory

Imaging Science, OCAMS and Bennu
Modern planetary imagers operate at ever-greater resolution, throughput and data loading. Their scientific goals remain the same: 1) reveal new solar system phenomenon, 2) document the visual history of its surfaces and 3) provide a context for physical and chemical anyalysis of meteorites and in situ samples. The trio of imagers in the OSIRIS-REx Camera Suite-OCAMS-are reviewed from that point of view. OCAMS' expected scientific return is discussed while noting the suite's critical function as a mission system to enable the selection of a primary sample site. In addition, Bennu's status as a microgravity object is emphasized. It will serve as a high-fidelity and readily observable physical analog to the many million billion planetesimals that contributed to the formation of the planets and that, directly or indirectly, currently populate the Kuiper Belt, Oort Cloud, Jovian Trojan points and, perhaps, the Main Belt and Near-Earth Asteroid populations.
Kuiper Space Sciences: Room 312