Ivanova O. Physical and dynamical properties of active small bodies of the Solar System

The present work is devoted to a comprehensive study of the physical, chemical, and dynamical properties of comets of different dynamic classes, active asteroids and centaurs, using the results of photometric, polarimetric, and spectral observations and numerical modeling. Based on the obtained large amount of observational data, the physical properties and chemical composition of active objects of different populations are determined and the peculiarities of their behavior during the demonstration of non-stationary processes are investigated. For the first time, distributions of brightness, color, and polarization over the comas of comets from different dynamic groups were obtained with high spatial resolution. It is shown that the interrelated variations of polarization and color in the comas, taking into account the depolarizing factors of molecular emissions and the nucleus, indicate the evolution of particle properties away from the nucleus and can diagnose the fragmentation rate of particles, their original sizes and composition. It has been established that the morphological structures detected by digital filtering methods in the comas of active small bodies of the Solar System are associated with certain active areas on their nuclei and have a specific distribution of polarization and color. It was shown for the first time that the degree of linear polarization of distant comets is systematically higher in comparison with the polarization of comets close to the Sun. By modeling the results of photometric, spectral and polarimetric observations using different models of particles, the material composition of dust particles in insects of distant comets was determined and its difference from the composition of dust in short-period comets was established. The mechanisms of ionization and outburst activity of comets at large distances from the Sun are proposed. To explain the activity of distant comets, the idea has been put forward that the crystallization of amorphous ice in comets can be non-monotonic, given not only H2O ice, but also more volatile CO and CO2 ice, as well as the evolution of surface erosion. Dynamic simulations have shown that the outburst activity of comets, including some distant comets, can be caused by the collision of meteoroids with their surface.