Rublevskiy A. Determination of the size of color and silicate spots on the surface of the asteroid 4 Vesta.

The thesis is devoted to determination of the sizes of various formations on the surface of the asteroid 4 Vesta from spectral-photometric observations. The work is based on the television observations carried out at the 0.5 meter telescope of the Scientific Research Institute "Crimean Astrophysical Observatory". From the observed asteroid's spectra, synthetic color indices B-V and V-R were calculated. The frequency analysis of the time series of the color indices re-sulted in discovery of 19 spots on the asteroid's surface. The sizes of the spots were found to be within the range of 8.8 to 660 km. The largest spot size, if located at the latitude of 45 degrees on the asteroid's surface, is 460 km, which corresponds to the size of a large crater, detected by the Hubble Space Telescope. This is verification of correctness of the obtained results. Frequency analysis of variations in color V-R resulted in discovery of 20 spot sizes in the range of 9 to 400 km. A cosmogonic conclusion was made: the large craters detected from variations of V-R colour-index are older, while the blue spots, found in variations of B-V colours, are younger. The result confirms the finding made by Japanese scientists about existence of hydrates on the surface of asteroid 4 Vesta. During the implementation of identified requirements for observations that can be used for the spectral frequency method, in particular the constancy of light asteroid Sun. The estimation of the sizes of the colour and hydrosilicates spots on the surface of the asteroid 4 Vesta, by means of the spectral-frequency method, was made for the first time in the world. According to the results of ground surveys conducted on a small telescope, first defined the size of small spots on the asteroid's surface.