论文标题
在HD 143006磁盘中对弧和环结构进行建模
Modeling the arc and ring structures in the HD 143006 disk
论文作者
论文摘要
原星磁盘中的环和不对称性被认为是正在进行的行星形成的路标。在这项工作中，我们进行了三维辐射转移模拟，以建模围绕HD 143006的有趣磁盘，该磁盘具有三个灰尘环和明亮的弧。假定具有未对准的内部磁盘的复杂几何配置可以解释不对称结构。二维表面密度是通过迭代拟合ALMA数据构建的。我们发现，尘埃温度在未对准的边界处显示出明显的不连续性。环质量从系统上低于年轻的HL Tau磁盘中推断出的0.6至16mearth。弧占总尘埃质量的近20％。这种集中在局部区域的高质量粉尘粒与尘埃陷入涡流的机制是一致的。假设整个磁盘中的气体与盘状质量比为30，则密集和冷弧接近重力不稳定的阈值，而Toomre参数Q〜1.3。然而，我们对Q的估计依赖于未知气体与尘埃质量比的假设。采用较低的气体与盘状质量比将增加推断的Q值。需要对灰尘和气体线的高分辨率观测来阐明子结构的起源。
Rings and asymmetries in protoplanetary disks are considered as signposts of ongoing planet formation. In this work, we conduct three-dimensional radiative transfer simulations to model the intriguing disk around HD 143006 that has three dust rings and a bright arc. A complex geometric configuration, with a misaligned inner disk, is assumed to account for the asymmetric structures. The two-dimensional surface density is constructed by iteratively fitting the ALMA data. We find that the dust temperature displays a notable discontinuity at the boundary of the misalignment. The ring masses range from 0.6 to 16Mearth that are systematically lower than those inferred in the younger HL Tau disk. The arc occupies nearly 20% of the total dust mass. Such a high mass fraction of dust grains concentrated in a local region is consistent with the mechanism of dust trapping into vortices. Assuming a gas-to-dust mass ratio of 30 that is constant throughout the disk, the dense and cold arc is close to the threshold of being gravitationally unstable, with the Toomre parameter Q~1.3. Nevertheless, our estimate of Q relies on the assumption for the unknown gas-to-dust mass ratio. Adopting a lower gas-to-dust mass ratio would increase the inferred Q value. Follow-up high resolution observations of dust and gas lines are needed to clarify the origin of the substructures.
