S. Bagnulo, M. A. Barucci , K. Muinonen, G. P. Tozzi, S. Fornasier, L. Kolokolova. Astronomical Observatory of Kharkiv National University (Sumska Str. 35, Kharkiv 61022, Ukraine, irina@astron.kharkov.ua), Armagh Observatory (College Hill, Armagh BT61 9DG, Northern Ireland, U.K. sba@arm.ac.uk), LESIA, Observatoire de Paris (5, pl. Jules Janssen, FR-92195 Meudon cedex, France, antonella.barucci@obspm.fr), Observatory, University of Helsinki (PO Box 14, 00014, Finland, muinonen@cc.helsinki.fi,) INAF Oss. Astrofisico di Arcetri (Largo E. Fermi 5, I-50125 Firenze, Italy, tozzi@arcetri.astro.it), University of Paris 7 ”Denis Diderot” (10 rue Alice Domon et Leonie Duquet, 75013 Paris, France, sonia.fornasier@obspm.fr), University of Maryland (College Park, MD, USA, ludmilla@astro.umd.edu).