IDA LIGHTCURVES - CONSISTENCY WITH GALILEO SHAPE AND PHOTOMETRIC MODELS

Models for the shape and global photometric behavior of 243 Ida derive d from Galileo images have been used to model the asteroid's telescopi c lightcurves. We find excellent agreement between the calculated and observed times of lightcurve extrema, confirming the sidereal rotation period of 4.633532 +/- 0.000007 hr determined by Binzel et al. (1993. Icarus 105, 310-325.). The shapes and amplitudes of the synthetic and observed lightcurves agree with each other to within approximate to 0 .05 mag, and the average offset in absolute photometry between model a nd observation is only 0.01 mag. This consistency confirms the accurac y of the shape model derived for Ida by Thomas et al. (1996. Icarus 12 0, 20-32.) and supports the model of the asteroid's photometric behavi or developed by Helfenstein et al. (1996. Icarus 120, 48-65.). (C) 199 6 Academic Press, Inc.