On the Main Reasons of Brightness Variation in Magnetic CP Stars

On the basis of the data obtained in a 10-color photometric system, the light curves of more than 30 different (B0-F0) magnetic CP stars are analyzed. In accordance with the nature of brightness variation, they can be divided into three groups: (a) brightness variations occur synchronously in all the colors; (b) brightness variation depends on the wavelength and takes the minimum value within the λ5200 Å depression; (c) brightness variations occur in antiphase before and after the λ5200 Å depression. The variation of brightness in antiphase is explained by intensification of the λ5200 Å continuum depression, created mainly by rare earth elements, the excess of which reaches 4.5-6.0 dex in spots on the surfaces of these CP stars.