ИСТИНА

During the previous decade, more than 30 objects with some signs of activity were found in Main asteroid belt (MAB). Nearly a half of them are bodies of ~1-km or less in size, so called main-belt comets (MBCs), which had signs of a stronger (comet-like) activity. We consider results of new spectrophotometric observations of eight main-belt primitive asteroids, in the depths of which water ice can survive, passed near perihelion distances in the present period of solar activity rise. Some of them displayed different signs of sublimation activity judging by the changes of their reflectance spectra (RSs). Analysis of the RSs are based on our previous observational data and results, as well as on their numerical simulations. Possible reasons of formation of a thin or thick dusty exosphere around the asteroids are discussed.