论文标题
异形磁盘MWC 758的不对称灰尘环中的螺旋臂子结构
Spiral-Arm Sub-Structures in the Asymmetrical Dust Rings of the Circumstellar Disk MWC 758
论文作者
论文摘要
磁盘中的不对称特征提供了嵌入式物体（例如行星）的间接证据。用Atacama大毫米/亚毫米阵列（ALMA）观察到的MWC 758中的双磁盘在0.9毫米的波长下追踪的，具有高达0.1“（15 au）的角度分辨率的波长为0.9毫米的波长，它具有不对键的尘埃，并呈现出较小的尘埃。方位角。对于每个段，我们将两个高斯函数拟合到径向强度的曲线，而所获得的最佳拟合参数作为方位角的函数。自由参数的上限（〜0.2）与Benisty等人（2015年）所确定的相似。 （2018年），由于所采用的分析方法和图像的各个分辨率的差异，我们在磁盘西部的西部确定了不同的结构。
Asymmetrical features in disks provide indirect evidences of embedded objects, such as planets. Observed with the Atacama Large Millimeter/submillimeter Array (ALMA), the circumstellar disk in MWC 758 traced with thermal dust continuum emission at wavelengths of 0.9 mm with an angular resolution up to 0.1" (15 au) exhibits an asymmetrical dust ring with additional features. In order to analyze the structures azimuthally and radially, we split the dust ring into small segments in azimuth. For each segment, we fit two-Gaussian functions to the radial intensity profile. The obtained best-fit parameters as a function of azimuth are analyzed. Three spiral-like arm structures are identified. When fitting the 0.9 mm features with the spiral density wave theory using the WKB approximation, two sets of disk aspect ratios are found: one solution gives relatively low values (~0.03) while the other solution is at the upper bound of the free parameter (~0.2). The planet locations suggested by the upper-bound result are similar to the ones determined by Benisty et al. (2015) for the NIR polarized intensity image. Comparing the reported spiral-like structures with the higher angular-resolution (0.04") ALMA image in Dong et al. (2018), we identify different structures in the West of the disk due to differences in the adopted analysis methods and the respective resolutions of the images.
