Adaptive Optics Imaging of the Circumbinary Disk around the T Tauri Binary UY Aurigae: Estimates of the Binary Mass and Circumbinary Dust Grain Size Distribution
Adaptive Optics Imaging of the Circumbinary Disk around the T Tauri Binary UY Aurigae: Estimates of the Binary Mass and Circumbinary Dust Grain Size Distribution
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T Tauri 双星 UY Aurigae 周围的环星盘的自适应光学成像：双星质量和环星尘粒尺寸分布的估计
DOI：
10.1086/305672
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
D. Potter
中科院分区：
文献类型：
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作者：
L. Close;A. Dutrey;François Roddier;S. Guilloteau;C. Roddier;M. Northcott;F. Ménard;Gilles Duvert;J. Graves;D. Potter
利用美国夏威夷大学的自适应光学仪器获得了UY Aur双星在J、H和K'点的高分辨率（FWHM = 0.″15）深像。我们清楚地探测到一个R ~ 500 Au的环双星盘，使UY Aur成为第二个被证实的环双星盘的年轻双星。我们发现，在K '、H和J处，盘的近侧亮度分别是远侧的2.6、2.7和6.5倍。原始的GG Tau环双星盘已经被重新检查，发现在K '，H和J处有相似的流量比，分别为1.5，2.6和3.6。一个现实的幂律分布（p = 4.7）的球形尘埃聚集体（由硅酸盐，无定形碳，石墨），再现所观察到的ISM消光曲线也预测这些观察到的流量比米氏散射理论。我们发现前向散射优于后向散射的观测结果与amin = 0.03 μm至amax = 0.5-0.6 μm范围内的Mie散射很好地拟合（全局χ2最小化）。散射观测结果不支持颗粒半径大于0.6 μm的大量存在。根据观测到的盘倾角，我们推导出UY Aur的轨道，其质量为1.6−0.67+0.47 M。根据观测到的UY Aur A和B的K7和M0谱型，建立了中心星周围内盘的吸积盘模型.模型表明，在B和A周围存在小的（下限R ~ 5-10 Au）内盘。看来B的吸积速度比A快约5倍，并且两个内部盘可能在约102-103年内耗尽，而无需来自外环联星盘的补充。我们的图像显示，这些内部的圆盘可能确实是通过渗透到环双星圆盘内部的薄流来补充物质的。目前看来，这样的流光可能是一个接近UY Aur B。我们的红外图像和气体的毫米图像的比较清楚地表明，在我们的红外图像中看到的尘埃跟踪环双星盘中的气体，就像GG Tau的情况一样。
We have obtained high-resolution (FWHM = 0.″15) deep images of the UY Aur binary at J, H, and K' with the University of Hawaii adaptive optics instrument. We clearly detect an R ~ 500 AU circumbinary disk discovered with millimeter interferometry, making UY Aur the second young binary with a confirmed circumbinary disk. It appears that the disk is inclined ~42° from face on. We find that the near side of the disk is brighter than the far side by factors of 2.6, 2.7, and 6.5 times at K', H, and J, respectively. The original GG Tau circumbinary disk has been reexamined and is found to have similar flux ratios of 1.5, 2.6, and 3.6 at K', H, and J, respectively. A realistic power-law distribution (p = 4.7) of spherical dust aggregates (composed of silicates, amorphous carbon, and graphite) that reproduces the observed ISM extinction curve also predicts these observed flux ratios from Mie scattering theory. We find the observed preference of forward-scattering over back-scattering is well fitted (global χ2 minimization) by Mie scattering off particles in the range amin = 0.03 μm to amax = 0.5-0.6 μm. The existence of a significant population of grain radii larger than 0.6 μm is not supported by the scattering observations. Based on the observed disk inclination we derive an orbit for UY Aur where the mass for the binary is 1.6−0.67+0.47 M☉. Based on the observed K7 and M0 spectral types for UY Aur A and B, accretion disk models for the inner disks around the central stars were constructed. The models suggest that small (lower limit R ~ 5-10 AU) inner disks exist around B and A. It appears that B is accreting ~5 times faster than A, and that both inner disks may be exhausted in ~102-103 yr without replenishment from the outer circumbinary disk. Our images suggest that these inner disks may indeed be resupplied with material through thin streamers of material that penetrate inside the circumbinary disk. Currently it appears that such a streamer may be a close to UY Aur B. Comparison of our IR images and the millimeter images of the gas clearly show that the dust seen in our IR images traces the gas in the circumbinary disk, as was also the case with GG Tau.