ON THE NATURE OF THE HERBIG B[e] STAR BINARY SYSTEM V921 SCORPII: GEOMETRY AND KINEMATICS OF THE CIRCUMPRIMARY DISK ON SUB-AU SCALES
ON THE NATURE OF THE HERBIG B[e] STAR BINARY SYSTEM V921 SCORPII: GEOMETRY AND KINEMATICS OF THE CIRCUMPRIMARY DISK ON SUB-AU SCALES
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HERBIG B[e]星双星系统V921 SCORPII的性质：亚AU尺度上的圆周盘的几何和运动学
DOI：
10.1088/0004-637x/752/1/11
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
G. Weigelt
中科院分区：
文献类型：
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作者：
S. Kraus;N. Calvet;L. Hartmann;K. Hofmann;A. Kreplin;J. Monnier;G. Weigelt
天蝎座V921是一个近距离双星系统（距离为0.“025），具有B[e]-现象。该系统被一个神秘的双极星云包围，这可能是由偶发的质量损失事件形成的，可能是由伴星和环主星盘之间的动力学相互作用触发的。在本文中，我们调查的空间结构和运动学的环主盘，目的是获得新的见解仍然强烈争论的进化阶段。为此，我们联合收割机首次将红外光谱干涉测量（VLTI/AMBER，λ/Δλ = 12，000）和光谱天体测量（VLT/CRIRES，λ/Δλ = 100，000）结合起来，这使我们能够以前所未有的3 km s−1的速度分辨率研究星周气体和尘埃的AU尺度分布。利用与模型无关的光心分析技术，我们发现Brγ射线发射气体与尘埃盘在同一平面内旋转。我们可以用开普勒旋转圆盘模型再现波长微分的能级和相位以及双峰谱线轮廓。中心星星的质量为5.4 ± 0.4 M·（d/1150 pc），这比光谱分类中预期的要低得多，表明V921 Sco可能比通常假设的更遥远（d = 2 kpc）。利用我们的Brγ光谱干涉数据和Paschen、Brackett和Pfund在61个氢复合谱线跃迁中的谱线衰减测量提供的几何信息，我们推导出了谱线发射气体的密度（Ne =（2-6）× 1019 m−3）。考虑到我们的测量结果可以用开普勒速度场再现，而没有流出的速度分量，并且没有检测到年龄指示光谱诊断，我们的研究为V921 Sco的前主序性质提供了新的证据。
V921 Scorpii is a close binary system (separation 0.″025) showing the B[e]-phenomenon. The system is surrounded by an enigmatic bipolar nebula, which might have been shaped by episodic mass-loss events, possibly triggered by dynamical interactions between the companion and the circumprimary disk. In this paper, we investigate the spatial structure and kinematics of the circumprimary disk, with the aim to obtain new insights into the still strongly debated evolutionary stage. For this purpose, we combine, for the first time, infrared spectro-interferometry (VLTI/AMBER, λ/Δλ = 12, 000) and spectro-astrometry (VLT/CRIRES, λ/Δλ = 100, 000), which allows us to study the AU-scale distribution of circumstellar gas and dust with an unprecedented velocity resolution of 3 km s−1. Using a model-independent photocenter analysis technique, we find that the Brγ-line-emitting gas rotates in the same plane as the dust disk. We can reproduce the wavelength-differential visibilities and phases and the double-peaked line profile using a Keplerian-rotating disk model. The derived mass of the central star is 5.4 ± 0.4 M☉ · (d/1150 pc), which is considerably lower than expected from the spectral classification, suggesting that V921 Sco might be more distant (d ∼ 2 kpc) than commonly assumed. Using the geometric information provided by our Brγ spectro-interferometric data and Paschen, Brackett, and Pfund line decrement measurements in 61 hydrogen recombination line transitions, we derive the density of the line-emitting gas (Ne = (2–6) × 1019 m−3). Given that our measurements can be reproduced with a Keplerian velocity field without an outflowing velocity component and the non-detection of age-indicating spectroscopic diagnostics, our study provides new evidence for the pre-main-sequence nature of V921 Sco.