ON THE NATURE OF THE HERBIG B[e] STAR BINARY SYSTEM V921 SCORPII: DISCOVERY OF A CLOSE COMPANION AND RELATION TO THE LARGE-SCALE BIPOLAR NEBULA
ON THE NATURE OF THE HERBIG B[e] STAR BINARY SYSTEM V921 SCORPII: DISCOVERY OF A CLOSE COMPANION AND RELATION TO THE LARGE-SCALE BIPOLAR NEBULA
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关于赫比格 B[e] 星双星系统 V921 SCORPII 的性质：亲密伴星的发现及其与大尺度双极星云的关系
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发表时间：
2012
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通讯作者：
G. Weigelt
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作者：
S. Kraus;N. Calvet;L. Hartmann;K. Hofmann;A. Kreplin;J. Monnier;G. Weigelt
天蝎座V921属于B[e]星群，与强烈的红外过剩以及允许和禁止的线发射有关，表明存在低密度和高密度的星周气体和尘埃。V921 Sco和其他B[e]星的许多方面仍然是神秘的，包括它们的演化状态和导致类定义特征的物理条件。在这封信中，我们使用甚大望远镜干涉仪/琥珀光谱干涉仪来重建高分辨率（λ/2B = 0）。″0013)在1.65,2.0和2.3 μm左右的三个波长波段的模型无关干涉图像。在我们的图像中，我们在V921 Sco周围发现了一个近距离（25.0±0.8 mas，对应于1.15 kpc的~ 29±0.9 AU）的伴星。在2008年和2009年的两个时期之间，我们测量到轨道运动为~ 7°，这意味着轨道周期为~ 35年（对于圆形轨道）。在主星周围，我们发现了一个圆盘状的结构，有径向温度梯度的迹象。这个au尺度圆盘的极轴与嵌入V921 Sco的弧分尺度双极星云对齐。利用麦哲伦/IMACS成像，我们在星云中探测到多层弧形亚结构，表明该系统的偶发性流出活动周期为~ 25年，大致与伴星的估计轨道周期相匹配。我们的研究支持了B[e]现象与紧密双星系统中的动力学相互作用有关的假设。
Belonging to the group of B[e] stars, V921 Scorpii is associated with a strong infrared excess and permitted and forbidden line emission, indicating the presence of low- and high-density circumstellar gas and dust. Many aspects of V921 Sco and other B[e] stars still remain mysterious, including their evolutionary state and the physical conditions resulting in the class-defining characteristics. In this Letter, we employ Very Large Telescope Interferometer/AMBER spectro-interferometry in order to reconstruct high-resolution (λ/2B = 0.″0013) model-independent interferometric images for three wavelength bands around 1.65, 2.0, and 2.3 μm. In our images, we discover a close (25.0 ± 0.8 mas, corresponding to ∼29 ± 0.9 AU at 1.15 kpc) companion around V921 Sco. Between two epochs in 2008 and 2009, we measure orbital motion of ∼7°, implying an orbital period of ∼35 years (for a circular orbit). Around the primary star, we detect a disk-like structure with indications for a radial temperature gradient. The polar axis of this AU-scale disk is aligned with the arcminute-scale bipolar nebula in which V921 Sco is embedded. Using Magellan/IMACS imaging, we detect multi-layered arc-shaped substructure in the nebula, suggesting episodic outflow activity from the system with a period of ∼25 years, roughly matching the estimated orbital period of the companion. Our study supports the hypothesis that the B[e] phenomenon is related to dynamical interaction in a close binary system.