Photometry and models of selected main belt asteroids - VII. 350 Ornamenta, 771 Libera, and 984 Gretia

We analyze photometric observations of the three main-belt asteroids 350 Ornamenta, 771 Libera, and 984 Gretia, conducted over a twelve-year interval. Our data and those of other authors allow us to determine pole and shape models using the lightcurve inversion technique. In all three cases, a single pole solution was obtained without any significant mirror solution: Ornamenta ― P = 9.180414 h, λ p = 184', β p = ―29° Libera ― P = 5.890423 h, λ p = 64°, β p = ―78° Gretia ― P = 5.778 025 h, λ p = 245°, β p = +52°. This analysis and the development of asteroid models increase the set of asteroids with known spin and shape parameters, which consists of only around 100 objects.