In remote observations of a planet with the elliptic orbit around the central star, the planet brightness varies considerably with phase angle. The spatial indicatrice of the visible layer reflection in continuous spectrum for a giant planet is basically determined by optical properties and the function of particle sizes distribution at the levels of the leaving radiation formation. We estimate some parameters of aerosols and calculate the spectral distributions of the brightness of the disc of a planet for a phase angle from 0° to 180°. With the use of these data the values of spherical albedo, geometrical albedo, and the phase functions for a planet are determined as well as the relative change of the integral brightness for a planet revolving around the central star is calculated. Our results show that, for some star systems, the possibility exists of reconstructing orbital phase curves. This allows one to improve the estimate of the inclination of the orbital plane to the picture plane and, in some cases, this can increase the estimate of the mass of an exoplanet almost by a factor of 6.