Veiling of Photosphere Lines in the Spectra of UX ORI Stars at Deep Light Minima. I. The Star RR Tau

The spectra of RR Tau star, which belongs to the family of young irregular variable UX Ori type stars, in its different brightness states have been studied using a comparative analysis. Selected spectra of the star that are obtained with the Nordic Optical Telescope at various times when its brightness ranged from ${10.6}^m$ to ${13.9}^m$ have been presented. The veiling of spectral lines at brightness minima by circumstellar emission has been considered, and its origin has been discussed.