Asteroids with unusual lightcurves: 14 Irene and 51 Nemausa

Some asteroids with peculiar light curves were chosen for more detail investigation. We present the first results of that study. Observations were obtained in 1989 and 1990 using the 70-cm telescope of Kharkov Observatory; the 40-cm telescope of Abastumani Observatory (Georgia), and the 60-cm telescope of the Main Astronomical Observatory of Ukrainian Academy of Sciences (Mt. Majdanak, Middle Asia). Observations and their reduction were carried out in a standard way. The aspect data, absolute magnitude of primary maximum, and lightcurve amplitude are given

Refining the asteroid taxonomy by polarimetric observations

International audienceWe present new results of polarimetric observations of 15 main belt asteroids of different composition. By merging new and published data we determined polarimetric parameters characterizing individual asteroids and mean values of the same parameters characterizing different taxonomic classes. The majority of asteroids show polarimetric phase curves close to the average curve of the corresponding class. We show that using polarimetric data it is possible to refine asteroid taxonomy and derive a polarimetric classification for 283 main belt asteroids. Polarimetric observations of asteroid (21) Lutetia are found to exhibit possible variations of the position angle of the polarization plane over the surface