Modeling of Hydrogen Emission Lines in the Spectrum of UX Ori in Its Bright State and during Eclipses

— The hydrogen spectrum of the UX Ori-type star is modeled in a bright state and during an eclipse by an opaque dusty fragment of its own protoplanetary disk. The disk wind is considered as the main source of the emission spectrum. The radiation generated in the stellar magnetosphere is also taken into account. We showed that variations in the Hα line profile during eclipses depend sensitively on the wind opening angle. In models with a large opening angle, the emission line at the minimum brightness becomes single, asymmetric, and shifts towards the red end, which contradicts the observations made in 1992 during the deep minimum of UX Ori, when the asymmetric two-peak emission line turned into an asymmetric single and practically unbiased line. This indicates that one more source contributes to the emission spectrum, which is not occulted by an opaque screen at the moments of eclipses. As possible options, we considered (a) scattered radiation of a hypothetical dust halo in the polar region of the disk and (b) peripheral layers of the gas atmosphere of the disk, which are the source of the photoevaporation wind. To clarify the situation, new high-quality observations of the spectra of this type of star in deep minima are needed.