Gaps, Rings, and Non-Axisymmetric Structures in Protoplanetary Disks - From Simulations to ALMA Observations
Gaps, Rings, and Non-Axisymmetric Structures in Protoplanetary Disks - From Simulations to ALMA Observations
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DOI：
10.1051/0004-6361/201424693
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发表时间：
2014-11
影响因子：
6.5
通讯作者：
M. Flock;J. P. Ruge;N. Dzyurkevich;T. Henning;H. Klahr;S. Wolf
中科院分区：
文献类型：
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作者：
M. Flock;J. P. Ruge;N. Dzyurkevich;T. Henning;H. Klahr;S. Wolf
目标。阿塔卡马大型毫米/亚毫米阵列（阿尔马）最近对年轻恒星周围的圆盘进行的观测揭示了尘埃连续辐射的明显不对称性。在这项工作中，我们希望研究轴对称和非轴对称结构所产生的磁旋转不稳定性的外部区域的原行星盘。我们结合联合收割机的国家的最先进的数值模拟的结果与后处理辐射传输（RT）生成合成地图和预测ALMA。方法。我们进行了非理想的全球3D磁流体动力学（MHD）分层模拟的死区外边缘使用FARGO MHD代码PLUTO。恒星和磁盘的参数是从一个参数化的磁盘模型适用于拟合高角分辨率多波长观测的各种拱星磁盘。我们考虑了一颗质量为M <$= 0.5 M <$的恒星，其盘的总质量约为0.085 M <$。从给定的表面密度分布和Monte Carlo辐射传递一致地计算二维初始温度和密度分布。使用粉尘化学模型计算2D欧姆电阻率分布。我们考虑了两个值的灰尘与气体的质量比，10-2和10-4，这导致两个不同水平的磁耦合。初始磁场为垂直净通量场。辐射传输模拟进行了基于蒙特卡罗的三维连续RT代码MC 3D。由此产生的尘埃再发射提供了与ALMA.Results.模拟观测的基础。所有的模型都迅速陷入了混乱状态。基准模型与灰尘气体的质量比为10-2开发了一个大的间隙，然后由位于死区外缘的表面密度的跳跃。密度和压力的跳跃足以阻止粒子在这个位置的径向漂移。此外，我们观察到的Rossby波不稳定性的跳跃位置接近60 Au的旋涡的产生。涡旋以40个局部轨道的周期稳定地产生和破坏。RT结果和模拟的阿尔马观测预测，观测这些出现在没有行星的磁化盘中的大尺度结构是可行的。无论是在磁盘中的湍流波动，也没有具体的时间模型可以区分的基础上，高角分辨率的亚毫米观测。这同样适用于死区边缘的间隙和行星间隙之间的区别，湍流盘和简单未扰动盘之间的区别，以及涡旋产生的不对称性。
Aims. Recent observations by the Atacama Large Millimeter/submillimeter Array (ALMA) of disks around young stars revealed distinct asymmetries in the dust continuum emission. In this work we wish to study axisymmetric and non-axisymmetric structures that are generated by the magneto-rotational instability in the outer regions of protoplanetary disks. We combine the results of state-of-the-art numerical simulations with post-processing radiative transfer (RT) to generate synthetic maps and predictions for ALMA.Methods. We performed non-ideal global 3D magneto-hydrodynamic (MHD) stratified simulations of the dead-zone outer edge using the FARGO MHD code PLUTO. The stellar and disk parameters were taken from a parameterized disk model applied for fitting high-angular resolution multi-wavelength observations of various circumstellar disks. We considered a stellar mass of M∗ = 0.5 M⊙ and a total disk mass of about 0.085 M∗. The 2D initial temperature and density profiles were calculated consistently from a given surface density profile and Monte Carlo radiative transfer. The 2D Ohmic resistivity profile was calculated using a dust chemistry model. We considered two values for the dust-to-gas mass ratio, 10-2 and 10-4, which resulted in two different levels of magnetic coupling. The initial magnetic field was a vertical net flux field. The radiative transfer simulations were performed with the Monte Carlo-based 3D continuum RT code MC3D. The resulting dust reemission provided the basis for the simulation of observations with ALMA.Results. All models quickly turned into a turbulent state. The fiducial model with a dust-to-gas mass ratio of 10-2 developed a large gap followed by a jump in surface density located at the dead-zone outer edge. The jump in density and pressure was strong enough to stop the radial drift of particles at this location. In addition, we observed the generation of vortices by the Rossby wave instability at the jump location close to 60 AU. The vortices were steadily generated and destroyed at a cycle of 40 local orbits. The RT results and simulated ALMA observations predict that it is feasible to observe these large-scale structures that appear in magnetized disks without planets. Neither the turbulent fluctuations in the disk nor specific times of the model can be distinguished on the basis of high-angular resolution submillimeter observations alone. The same applies to the distinction between gaps at the dead-zone edges and planetary gaps, to the distinction between turbulent and simple unperturbed disks, and to the asymmetry created by the vortex.