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M.C. Nolan, J.-L. Margot, E.S. Howell, A.A. Hine, A. Crespo, V. Negrón, P.J. Perrilat (NAIC/Arecibo Obs.), C. Magri (U. Maine), S.J. Ostro, J.D. Giorgini (JPL/Caltech), D.B. Campbell (Cornell/NAIC)
During 2000 we have obtained radar images of asteroids 1~Ceres and 554~Peraga, and radar CW spectra of asteroids 2~Pallas, 7~Iris, 288~Glauke. By the time of the meeting, we also hope to have images of 393~Lampetia and 324~Bamberga, and spectra of 88~Thisbe, 111~Ate, 336~Lacadiera, and 914~Palisana. The CW observations include the beginning of a survey of main-belt asteroid properties. This survey aims to determine whether there is any relation between radar properties and composition. Such correlation could be due to either the chemical composition, or to the physical properties that could determine (e.g.\/) impact strengths.
Time-resolved near-infrared spectra of the D-class asteroid 336~Lacadiera show that the surface is compositionally inhomogeneous (Howell 1995). 88~Thisbe shows some variability at visible wavelengths, but is complicated by having a rotation period nearly commensurate with 24 hours. The upcoming observations include some asteroids that show an OH band at 3 microns, some which are variable, and some which lack this band. We plan to compare the spectral variability with the (time-resolved) radar properties of these objects, to determine whether radar properties correlate with composition.
The Arecibo Observatory is operated by Cornell University under a cooperative agreement with the National Science Foundation with additional funding from NASA.