Abstract—

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.

中文翻译：

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UX Ori光谱中明亮状态和日食期间氢排放线的建模

摘要-

UX Ori型恒星的氢光谱是在明亮状态下和日食期间通过其自身原行星盘的不透明尘土碎片模拟的。盘状风被认为是发射光谱的主要来源。还考虑了在恒星磁层中产生的辐射。我们发现日食期间Hα线剖面的变化敏感地取决于风的张开角度。在具有大打开角度的模型中，最小亮度的发射线变为单个，不对称并向红色端偏移，这与1992年在UX Ori的最小极深时（不对称的两峰发射线）的观察结果相矛盾。变成一条不对称的单一且几乎无偏的线。这表明有更多的源有助于发射光谱，日食时不透明的屏幕不会掩盖它。作为可能的选择，我们考虑了（a）假想的粉尘晕在圆盘的极性区域中的散射辐射，以及（b）圆盘的气体气氛的外围层，它们是光蒸发风的来源。为了澄清这种情况，需要对这种类型的恒星的深极小光谱进行高质量的新观测。