Physical Study of Outer Belt Asteroids

Abstract

Located in the proximity of Jovian resonances, the outer belt asteroids are kept from interacting with other asteroids and are likely to represent a population of primitive bodies. The systematic investigation of the physical properites of these objects and the subsequent understanding of their nature and origin, will have a direct implication for any theoretical study on the evolution of the solar system. In the last decade the information on the spectral and photometric properties of distant asteroids has strongly increased, leading to the formulation of specific questions, the answer to which will enable a comprehensive picture of this class of bodies. Since 1988 our group is carrying out a program devoted to the physical study of the Trojans and outer belt asteroids (Hilda and Cybele groups) to characterize their rotational properties, composition and shapes. During several observing campaigns, carried out at different observatories, reliable rotational periods andlight curve amplitudes have been determined for eight distant asteroids using both CCD and photoelectric photometry. We eill here present some preliminary results of our campaigns.