The Structure of Pre-transitional Protoplanetary Disks. II. Azimuthal Asymmetries, Different Radial Distributions of Large and Small Dust Grains in PDS 70
The Structure of Pre-transitional Protoplanetary Disks. II. Azimuthal Asymmetries, Different Radial Distributions of Large and Small Dust Grains in PDS 70
复制标题
过渡前原行星盘的结构。
DOI：
10.1088/0004-637x/799/1/43
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
J. ほか56名
中科院分区：
文献类型：
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作者：
Hashimoto;J. ほか56名
间隙盘（即过渡盘）的形成过程及其不对称性仍在争论中。所提出的盘-行星相互作用、光蒸发、颗粒生长、反气旋涡旋、偏心以及它们的组合将导致气体和小（亚μm尺寸）和大（毫米尺寸）尘埃颗粒的不同径向分布以及盘内结构的不对称。光学/近红外（NIR）成像观测和（亚）毫米干涉测量分别可以追踪小尘埃颗粒和大尘埃颗粒；因此，多波长观测有助于阐明圆盘复杂结构的起源。本文报道了亚毫米波阵列对围绕太阳质量恒星PDS 70的过渡前原行星盘在1.3 mm处的尘埃连续体和12 CO J= 2→1线发射的观测结果。PDS 70是一颗弱衬的金牛座T星，在近红外波长下，在其圆盘的散射光中显示出一个半径为~ 65 AU的间隙。然而，我们发现圆盘上有一个更大的间隙，在1.3 mm处半径为~ 80 AU。图像中所有三种盘成分（气体和大小尘埃颗粒）的辐射在盘的中心区域显示出亮度缺陷，特别是小尘埃颗粒和大尘埃颗粒的尘埃盘具有不对称的亮度。尘埃连续体中峰值位置与圆盘对面的通量密度之比达到1.4。我们认为PDS 70周围的不对称和不同的间隙半径可能是由几个（看不见的）吸积行星引起的尘埃过滤形成的。
The formation scenario of a gapped disk, ie, transitional disk, and its asymmetry is still under debate. Proposed scenarios such as disk–planet interaction, photoevaporation, grain growth, anticyclonic vortex, eccentricity, and their combinations would result in different radial distributions of the gas and the small (sub-μm size) and large (millimeter size) dust grains as well as asymmetric structures in a disk. Optical/near-infrared (NIR) imaging observations and (sub-) millimeter interferometry can trace small and large dust grains, respectively; therefore multi-wavelength observations could help elucidate the origin of complicated structures of a disk. Here we report Submillimeter Array observations of the dust continuum at 1.3 mm and 12 CO J= 2→ 1 line emission of the pre-transitional protoplanetary disk around the solar-mass star PDS 70. PDS 70, a weak-lined T Tauri star, exhibits a gap in the scattered light from its disk with a radius of∼ 65 AU at NIR wavelengths. However, we found a larger gap in the disk with a radius of∼ 80 AU at 1.3 mm. Emission from all three disk components (the gas and the small and large dust grains) in images exhibits a deficit in brightness in the central region of the disk, in particular, the dust disk in small and large dust grains has asymmetric brightness. The contrast ratio of the flux density in the dust continuum between the peak position to the opposite side of the disk reaches 1.4. We suggest the asymmetries and different gap radii of the disk around PDS 70 are potentially formed by several (unseen) accreting planets inducing dust filtration.