We present spectroscopic and photometric observations of Bernhard-2, which was previously identified as a candidate system that hosts a misaligned circumbinary disk. Our spectroscopic measurements confirm that Bernhard-2 indeed contains an eccentric (e = 0.69 ± 0.08) binary and thus that the periodic variability in the photometric light curve is best explained by the occultation by the misaligned circumbinary disk. By modeling the spectral energy distributions at different phases, we infer the masses of the two binary components to be ∼1.1 M⊙ and ∼0.9 M⊙, respectively. The system age is determined to be ≲20 Myr by combining the stellar isochrone model with lithium abundance. Our new photometric observations show clear deviations from the model prediction based on the archival data, suggesting ongoing precession of the circumbinary disk. The Hα line of Bernhard-2 also shows an inverse P-Cygni profile at epochs close to the pericenter passage, which could be attributed to the pulsed accretion around the pericenter. Bernhard-2 therefore closely resembles the well-studied KH 15D system. Further detailed observations and studies of such rare systems can provide useful information about disk physics and evolution.

中文翻译：

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具有未对齐的外循环二元圆盘的偏心二进制


我们介绍了 Bernhard-2 的光谱和光度观测结果，它之前被确定为承载未对准的环二元盘的候选系统。我们的光谱测量证实，Bernhard-2 确实包含一个偏心 （e = 0.69 ± 0.08） 双星，因此光度光曲线的周期性变化最好用未对准的环二星盘的掩星来解释。通过对不同相位的光谱能量分布进行建模，我们推断出两个二进制分量的质量分别为 ∼1.1 M⊙ 和 ∼0.9 M⊙。通过将恒星等时线模型与锂丰度相结合，确定系统年龄为 ≲20 Myr。我们新的光度观测结果显示，与基于档案数据的模型预测存在明显偏差，表明环二圆盘持续进动。Bernhard-2 的 Hα 线在靠近近心通道的时期也显示出逆 P-Cygni 剖面，这可能归因于近心周围的脉冲吸积。因此，Bernhard-2 与经过充分研究的 KH 15D 系统非常相似。对这种稀有系统的进一步详细观察和研究可以提供有关盘物理学和演化的有用信息。