The Eccentric Cavity, Triple Rings, Two-armed Spirals, and Double Clumps of the MWC 758 Disk
The Eccentric Cavity, Triple Rings, Two-armed Spirals, and Double Clumps of the MWC 758 Disk
复制标题
DOI：
10.3847/1538-4357/aac6cb
复制
发表时间：
2018-05
期刊：
影响因子：
--
通讯作者：
R. Dong;Sheng-Yuan Liu;J. Eisner;S. Andrews;J. Fung;Zhaohuan Zhu;E. Chiang;J. Hashimoto;H. Liu-H.
中科院分区：
文献类型：
--
作者：
R. Dong;Sheng-Yuan Liu;J. Eisner;S. Andrews;J. Fung;Zhaohuan Zhu;E. Chiang;J. Hashimoto;H. Liu-H.
原行星盘中的空间分辨结构暗示着看不见的行星。先前对MWC 758周围过渡盘的成像观察显示了一个内腔，一个环状外盘，发射团块和螺旋臂，所有这些都可能是由同伴产生的。我们在0.87 mm波长下以43 × 39 mas角分辨率（6.9 × 6.2 Au）和20 μJy光束−1 rms对MWC 758进行了阿尔马尘埃连续谱观测。中心的亚毫米波发射腔被发现是偏心的，一旦去投影，它的外缘可以很好地拟合一个椭圆，偏心率为0.1，一个焦点在星星上。宽环状的外盘被分解成三个狭窄的环，中间有两个间隙。外两个环暂时显示出与界定内腔的最内环相同的偏心率和取向。这两个先前已知的尘埃发射团在径向和方位角方向上都得到了分辨，径向宽度等于0.04 ×当地尺度高度。先前在近红外（NIR）散射光中成像的两个旋臂中只有一个在阿尔马尘埃发射中显示出来，由于投影效应，它的星心距离稍大。我们还提交的证据盘截断在100 Au的基础上比较近红外成像观测模型。螺旋星系、北星系团和被截断的星盘边缘大体上都与螺旋星系外大约100 Au处的一个伴星的存在相一致。
Spatially resolved structures in protoplanetary disks hint at unseen planets. Previous imaging observations of the transitional disk around MWC 758 revealed an inner cavity, a ring-like outer disk, emission clumps, and spiral arms, all possibly generated by companions. We present ALMA dust continuum observations of MWC 758 at 0.87 mm wavelength with 43 × 39 mas angular resolution (6.9 × 6.2 au) and 20 μJy beam−1 rms. The central submillimeter emission cavity is revealed to be eccentric; once deprojected, its outer edge can be well fitted by an ellipse with an eccentricity of 0.1 and one focus on the star. The broad ring-like outer disk is resolved into three narrow rings with two gaps in between. The outer two rings tentatively show the same eccentricity and orientation as the innermost ring bounding the inner cavity. The two previously known dust emission clumps are resolved in both the radial and azimuthal directions, with radial widths equal to ∼4× the local scale height. Only one of the two spiral arms previously imaged in near-infrared (NIR) scattered light is revealed in ALMA dust emission, at a slightly larger stellocentric distance owing to projection effects. We also submit evidence of disk truncation at ∼100 au based on comparing NIR imaging observations with models. The spirals, the north clump, and the truncated disk edge are all broadly consistent with the presence of one companion exterior to the spirals at roughly 100 au.