论文标题
限制Im Lup中的湍流和灰尘磁盘：行星形成的发作
Constraining the turbulence and the dust disk in IM Lup: onset of planetesimal formation
论文作者
论文摘要
原月球磁盘的观察提供了有关行星形成的信息以及行星系统多样性的原因。理解行星形成的关键是研究从小谷物到卵石的尘埃演化。较小的谷物与气体动力学耦合良好，它们的分布显着延伸到磁盘中平面上方。较大的谷物更快地沉降，并且仅在中平面中有效形成。通过结合近红外的偏振光和毫米观测，可以约束小晶粒和大晶粒的空间分布。我们旨在根据观察数据构建尘埃颗粒的尺寸分布和垂直/径向结构的详细模型。特别是，我们有兴趣恢复Im Lup Protoplanetary磁盘中的灰尘分布。我们创建了一个物理模型，用于原动性磁盘的灰尘分布，并模拟毫米连续体和近红外极化辐射的辐射转移。使用马尔可夫链蒙特卡洛法，我们将派生的图像与可用于IM LUP磁盘的观测值进行比较，以限制最佳的物理模型，以恢复垂直晶粒尺寸的分布。毫米和近红外发射严重限制了我们模型的灰尘质量和晶粒尺寸分布。我们发现灰尘分布中的尺寸分离，磁盘中平面中有毫米大小的晶粒。这些谷物是根据我们模型预测的短安定时间尺度在磁盘中有效形成的，可能是通过沉积驱动的凝结形成。这也表明在中平面中较小的半径上的高尘埃与气体比率很高，可能会触发内部磁盘中的流型不稳定性和行星形成。
Observations of protoplanetary disks provide information on planet formation and the reasons for the diversity of planetary systems. The key to understanding planet formation is the study of dust evolution from small grains to pebbles. Smaller grains are well-coupled to the gas dynamics, and their distribution is significantly extended above the disk midplane. Larger grains settle much faster and are efficiently formed only in the midplane. By combining near-infrared polarized light and millimeter observations, it is possible to constrain the spatial distribution of both the small and large grains. We aim to construct detailed models of the size distribution and vertical/radial structure of the dust particles in protoplanetary disks based on observational data. In particular, we are interested in recovering the dust distribution in the IM Lup protoplanetary disk. We create a physical model for the dust distribution of protoplanetary disks and simulate the radiative transfer of the millimeter continuum and the near-infrared polarized radiation. Using a Markov chain Monte Carlo method, we compare the derived images to the observations available for the IM Lup disk to constrain the best physical model for IM Lup and to recover the vertical grain size distribution. The millimeter and near-infrared emission tightly constrain the dust mass and grain size distribution of our model. We find size segregation in the dust distribution, with millimeter-sized grains in the disk midplane. These grains are efficiently formed in the disk, possibly by sedimentation-driven coagulation, in accord with the short settling timescales predicted by our model. This also suggests a high dust-to-gas ratio at smaller radii in the midplane, possibly triggering streaming instabilities and planetesimal formation in the inner disk.
