PRE-TRANSITIONAL DISK NATURE OF THE AB Aur DISK
PRE-TRANSITIONAL DISK NATURE OF THE AB Aur DISK
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DOI：
10.1088/2041-8205/718/2/l199
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发表时间：
2010-07
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通讯作者：
M. Honda;A. Inoue;Y. Okamoto;H. Kataza;M. Fukagawa;T. Yamashita;T. Fujiyoshi;M. Tamura;J. Hashimoto;T. Miyata;S. Sako;I. Sakon;H. Fujiwara;T. Kamizuka;T. Onaka
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作者：
M. Honda;A. Inoue;Y. Okamoto;H. Kataza;M. Fukagawa;T. Yamashita;T. Fujiyoshi;M. Tamura;J. Hashimoto;T. Miyata;S. Sako;I. Sakon;H. Fujiwara;T. Kamizuka;T. Onaka
利用8.2 m斯巴鲁望远镜上的冷却中红外相机和光谱仪对AB Aur周围的圆盘进行了24.6 μm的成像和分辨。在源尺寸的半最大值处，高斯全宽估计为90±6 AU，表明圆盘在24.6 μm处比在更短的波长处延伸得更远。为了解释扩展后的24.6 μm图像，我们考虑了一个表面密度减小的圆盘，其边界半径为Rc，这是由于射电观测表明，在距离恒星约100 AU的范围内存在一个减小的内部区域。引入表面密度折减因子fc，在Rc = 88 AU, fc = 0.01的条件下，与观测到的24.6 μm径向强度分布图匹配最佳。我们认为在24.6 μm处的发射扩展是由于在边界半径处（外盘的内缘）的壁状结构的发射增强，这是由Rc处表面密度的跳跃引起的。这种缩小的内盘和几何上厚的外盘结构也可以解释更短波长下的点状性质。我们还注意到，这个磁盘的几何形状在性质上与过渡前磁盘相似，这表明AB Aur磁盘处于过渡前磁盘阶段。
The disk around AB Aur was imaged and resolved at 24.6 μm using the Cooled Mid-infrared Camera and Spectrometer on the 8.2 m Subaru Telescope. The Gaussian full width at half-maximum of the source size is estimated to be 90 ± 6 AU, indicating that the disk extends further out at 24.6 μm than at shorter wavelengths. In order to interpret the extended 24.6 μm image, we consider a disk with a reduced surface density within a boundary radius Rc, which is motivated by radio observations that suggest a reduced inner region within about 100 AU from the star. Introducing the surface density reduction factor fc for the inner disk, we determine that the best match with the observed radial intensity profile at 24.6 μm is achieved with Rc = 88 AU and fc = 0.01. We suggest that the extended emission at 24.6 μm is due to the enhanced emission from a wall-like structure at the boundary radius (the inner edge of the outer disk), which is caused by a jump in the surface density at Rc. Such a reduced inner disk and geometrically thick outer disk structure can also explain the more point-like nature at shorter wavelengths. We also note that this disk geometry is qualitatively similar to a pre-transitional disk, suggesting that the AB Aur disk is in a pre-transitional disk phase.