On the Scattered Radiation Spectrum of Protoplanetary Disks

The deformation of the photospheric radiation of a young star during scattering in the inner regions of the protoplanetary disk has been studied. The distortion of spectral lines occurs as a result of a variation in the radiation frequency due to the Doppler effect upon scattering by moving dust particles. It has been shown that strong variations in the photospheric lines in the spectrum of the T Tauri star RW Aur, observed during its deep minimum, were caused by radiation scattering by dust particles closest to the star. In the case of hot UX Ori stars, the distortion of photospheric lines during scattering is less significant (with rare exceptions), since the dust sublimation zone is much farther from the star, and the photospheric lines themselves are broadened by the rapid rotation of stars.