御夫座 UX 型变星 AS442A 这颗金牛座 Ae/Be 星
Herbig AeBe Star AS442A as a UXOR-type system
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中文总结 AI 辅助
研究聚焦暗弱 HAeBe 恒星 AS 442A，结合存档测光与光谱观测，统计约 3500 次测量探究其光谱和光度变异性，发现周期性食可解释其类似御夫座 UX 型变星的亮度下降，揭示伴星轨道特性与恒星变异性的关系。
中文摘要 AI 辅助
对年轻的中等质量金牛座 Ae/Be（HAeBe）恒星的物理特性进行详细研究，需要长期收集大量同类观测数据。本文展示了一项针对暗弱的 HAeBe 恒星 AS 442A 的多年研究成果。本研究旨在利用长期存档测光数据以及我们自己的光谱观测，来探究该恒星的光谱和光度变异性。通过对 1984 年至 2025 年约 3500 次存档测量进行统计研究长期光度变异性。此外，利用 2020 年至 2024 年在沙马基天体物理观测台（ShAO）获得的数据检查恒星的光谱变异性。在 1990 年、2013 年和 2023 年检测到三个最深的亮度极小值，U 波段振幅约为 2 星等，其他波段高达约 1 星等。所有三个观测到的深极小值之前和之后都伴有较小的亮度下降。主光变曲线和色-星等图显示出御夫座 UX 型变星特有的“蓝化”效应。首次检测到深度亮度极小值以 P = 3759 +/- 35 天的周期准周期性出现。我们的光谱观测在 2023 年最后一次深度光变暗之前进行。我们表明，观测到的光谱变异性，特别是发射线增强以及吸收线深度和宽度减小，主要与恒星的亮度变化有关。我们首次表明，HAeBe 恒星 AS 442A 类似御夫座 UX 型变星的亮度下降的主要原因可以用双星系统中的周期性食来解释。一个作为晚型伴星的紧密伴星，其轨道半长轴（a>7.5 天文单位）可能导致观测到的恒星变异性。
英文摘要
Detailed studies of the physical characteristics of young intermediate-mass Herbig Ae/Be (HAeBe) stars require extensive sets of homogeneous observational data collected over long periods. In this paper, we present the results of a multi-year study focusing on the faint Herbig Ae/Be star AS 442A. The goal of this study was to investigate the spectral and photometric variability of the star, utilizing long-term archival photometry alongside our own spectroscopic observations. The long-term photometric variability was statistically investigated using approximately 3,500 archival measurements spanning 1984 to 2025. Additionally, we examined the star's spectral variability using data obtained at the Shamakhy Astrophysical Observatory (ShAO) between 2020 and 2024. The three deepest brightness minima were detected in 1990, 2013, and 2023, with amplitudes of approximately ~2 mag in the U-band and up to ~1 mag in other bands. All three observed deep minima were accompanied by smaller brightness dips occurring both before and after the main event. The main light curve and color-magnitude diagrams show the "blueing" effect, which is characteristic of UXOR stars. A quasi-periodic occurrence of deep brightness minima with a period of P = 3759 +/- 35 days was detected for the first time. Our spectral observations were performed before the last deep light fading, which occurred in 2023. We show that the observed spectral variability, specifically the strengthening of emission lines and the reduction in depths and widths of absorption lines, is primarily related to the star's brightness variations. We have shown for the first time that the main reason for the UXOR-like brightness dip of the HAeBe star AS 442A can be explained by a periodic eclipse in a binary system. A close companion as a late-type secondary star with an orbit semimajor axis (a>7.5 au) likely drives the observed stellar variability.
