Dr. Christopher Magri, at the University of Maine, will use the upgraded radar system at the Arecibo Observatory to study carbonaceous main-belt asteroids (MBAs). He will use radar-derived constraints on target shape, topography, rotation state, composition, and near-surface roughness to define similarities and differences between the various taxonomic classes containing dark objects and between carbonaceous MBAs and other asteroids. This project, a continuation of NSF-supported research carried out since 1999, is a logical outgrowth of Dr. Magri's recent statistical analyses of MBAs detected prior to the facility upgrade. Carbonaceous asteroids are thought to be relatively unaltered from the primordial solids which condensed in the outer solar nebula; the outermost ones probably have complex organic molecules on their surfaces. This is the first time that large numbers of such objects have been detectable by radar. Hence, Dr. Magri's work represents a step toward understanding the origin and evolution of our solar system. ***
