A Millimeter-multiwavelength Continuum Study of VLA 1623 West
A Millimeter-multiwavelength Continuum Study of VLA 1623 West
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DOI：
10.3847/1538-4357/ac905c
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发表时间：
2022-09
期刊：
影响因子：
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通讯作者：
A. Michel;S. Sadavoy;P. Sheehan;L. Looney;E. Cox
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作者：
A. Michel;S. Sadavoy;P. Sheehan;L. Looney;E. Cox
VLA 1623 West是一个模糊的来源，被描述为一个冲击云以及原恒星盘。我们使用深阿尔马1.3和0.87毫米的观测，以限制其形状和结构，以确定其起源更好。我们使用一系列的几何模型来拟合在两个波长与GALARIO的紫外可见光。虽然真实的天体显示出类似于原行星盘中被确定为间隙和环的结构，但我们发现，在高倾角下修改后的平顶高斯模型提供了最佳的观测结果。这种拟合与对光学厚度大、高度倾斜的盘的预期吻合得很好。然而，我们发现，几何模型始终产生积极的残差在四个角落的磁盘在两个波长。我们解释这些残留物作为证据，磁盘是在毫米尘埃耀斑。我们使用一个简单的玩具模型的边缘上的喇叭形磁盘，并发现残差最好匹配的磁盘与喇叭形，主要限于在R Au的外盘。因此，VLA 1623 W可能代表一个年轻的原恒星盘，其中大的尘埃颗粒还没有足够的时间进入中平面。这一结果可能会对磁盘演化和垂直尘埃沉降如何影响导致行星形成的初始条件产生影响。
VLA 1623 West is an ambiguous source that has been described as a shocked cloudlet as well as a protostellar disk. We use deep ALMA 1.3 and 0.87 mm observations to constrain its shape and structure to determine its origins better. We use a series of geometric models to fit the uv visibilities at both wavelengths with GALARIO. Although the real visibilities show structures similar to what has been identified as gaps and rings in protoplanetary disks, we find that a modified flat-topped Gaussian model at high inclination provides the best fit to the observations. This fit agrees well with expectations for an optically thick, highly inclined disk. Nevertheless, we find that the geometric models consistently yield positive residuals at the four corners of the disk at both wavelengths. We interpret these residuals as evidence that the disk is flared in the millimeter dust. We use a simple toy model for an edge-on flared disk and find that the residuals best match a disk with flaring that is mainly restricted to the outer disk at R ≳ 30 au. Thus, VLA 1623W may represent a young protostellar disk where the large dust grains have not yet had enough time to settle into the midplane. This result may have implications for how disk evolution and vertical dust settling impact the initial conditions leading to planet formation.