Brown Bag Colloquium

Monday, Apr 28, 2014
12:00 pm — 1:00 pm

Location: Kuiper Space Sciences
Room: 309

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.