On rotational properties of asteroids

Rotational properties of 149 asteroids are analyzed. The data set consists of main-belt asteroids having periods and amplitudes determined by the photoelectric method. A statistical ground is given of the selection of the whole sample into three subclasses according to the asteroid size range. The dividing points are D approximately 50 km and approximately 200 km. The average rotation velocity is the largest for the asteroids with D > 200 km. No statistically significant correlation between the rotation velocity and the asteroids optical type have been found The estimate of density for the largest S-asteroids is obtained as well. It indicates that the surface material of these bodies is similar to iron-stony meteorites. This conclusion is in good agreement with the spectrometry data