Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
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DOI：
10.1051/0004-6361:20077759
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发表时间：
2008-03-01
影响因子：
6.5
通讯作者：
Henning, Th.
中科院分区：
文献类型：
--
作者：
Brauer, F.;Dullemond, C. P.;Henning, Th.
在原行星盘中，固体颗粒向米级尺寸的增长必须克服至少两个障碍，即由于径向漂移和破坏性碰撞导致的颗粒破碎而导致的材料快速损失。在本文中，我们提出了越来越多的现实物理涉及的数值模拟的结果。一步一步，我们包括各种效果，如粒子生长，径向/垂直粒子运动和尘埃粒子破碎在我们的模拟。我们证明了初始的尘气比是必不可少的颗粒，以克服径向漂移障碍。如果这个值与星际介质的标准值相比增加2倍，那么在10（4）年内，可以在内盘（< 2 Au）中形成km大小的物体。只有在发生碎裂所需的不切实际的高阈值速度（>30米/秒）下，颗粒才能在低α值的盘中生长到更大的尺寸。我们还发现，小于5%的小尘埃颗粒留在磁盘后，1百万年由于径向漂移，无论是否包括在模拟中的碎片或没有。在本文中，我们还提出了相当大的改进，现有的算法尘埃粒子凝聚，加快了凝聚方案的一个因素，类似于10（4）。
The growth of solid particles towards meter sizes in protoplanetary disks has to circumvent at least two hurdles, namely the rapid loss of material due to radial drift and particle fragmentation due to destructive collisions. In this paper, we present the results of numerical simulations with more and more realistic physics involved. Step by step, we include various effects, such as particle growth, radial/vertical particle motion and dust particle fragmentation in our simulations. We demonstrate that the initial dust-to-gas ratio is essential for the particles to overcome the radial drift barrier. If this value is increased by a factor of 2 compared with the canonical value for the interstellar medium, km-sized bodies can form in the inner disk (< 2 AU) within 10(4) yrs. However, we find that solid particles get destroyed through collisional fragmentation. Only with the unrealistically high-threshold velocities needed for fragmentation to occur (>30 m/s), particles are able to grow to larger sizes in disks with low a values. We also find that less than 5% of the small dust grains remain in the disk after 1 Myr due to radial drift, no matter whether fragmentation is included in the simulations or not. In this paper, we also present considerable improvements to existing algorithms for dust-particle coagulation, which speed up the coagulation scheme by a factor of similar to 10(4).