Stirring up the dust: a dynamical model for halo-like dust clouds in transitional disks
Stirring up the dust: a dynamical model for halo-like dust clouds in transitional disks
复制标题
搅动尘埃：过渡盘中晕状尘埃云的动力学模型
DOI：
10.1051/0004-6361/201116757
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发表时间：
2011
影响因子：
6.5
通讯作者：
C. Dominik
中科院分区：
文献类型：
--
作者：
S. Krijt;C. Dominik
上下文少数年轻的恒星天体除了有星周盘外，还显示出由光学上薄的尘埃组成的光环状结构。这个光环或圆环位于星星的几个Au之内，但它的起源还没有被理解。目标。一个动力激发的微行星云碰撞最终形成尘埃可能会产生这样的结构。动力学激发的原因可能是一个或多个行星，也许是在偏心轨道上，或者是一个迁移的行星。这项工作调查了一个向内迁移的行星，动态散射星子作为观察到的结构的可能原因。如果这种机制是负责的，那么观察到的类似光环的结构可以用来推断这些系统中行星的存在。方法.我们目前的最大倾角达到由于微行星和迁移行星之间的动力学相互作用的分析估计。此外，辛积分器被用来模拟迁移的行星上的星子人口的影响。碰撞的时间尺度估计由此产生的人口的星子和灾难性的碰撞中产生的尘埃的大小分布确定。结果研究发现，向内迁移的行星只有在物质位于偏心轨道上时，才能将其遇到的物质分散到高倾斜轨道上。这种偏心轨道可能是共振捕获和偏心泵送的结果。模拟结果表明，在一定的迁移率和行星质量范围内，共振捕获结合行星迁移确实会导致微行星到达偏心轨道，随后分散到高倾斜轨道。由此产生的尘埃的尺寸分布计算确定找到总质量和光学深度，这被发现比较合理，以及与观察到的结构。结论.由行星迁移引起的微行星的动力散射，随后将这些微行星研磨成尘埃颗粒，似乎是推断出的星周尘埃云的一个有希望的解释。还需要进一步的研究，看看光环是否可以用来推断行星的存在。
Context. A small number of young stellar objects show signs of a halo-like structure of optically thin dust, in addition to a circumstellar disk. This halo or torus is located within a few AU of the star, but its origin has not yet been understood. Aims. A dynamically excited cloud of planetesimals colliding to eventually form dust could produce such a structure. The cause of the dynamical excitation could be one or more planets, perhaps on eccentric orbits, or a migrating planet. This work investigates an inwardly migrating planet that is dynamically scattering planetesimals as a possible cause for the observed structures. If this mechanism is responsible, the observed halo-like structure could be used to infer the existence of planets in these systems. Methods. We present analytical estimates on the maximum inclination reached owing to dynamical interactions between planetesimals and a migrating planet. In addition, a symplectic integrator is used to simulate the effect of a migrating planet on a population of planetesimals. Collision time scales are estimated for the resulting population of planetesimals and the size distribution of the dust created in catastrophic collisions is determined. Results. It is found that an inwardly migrating planet is only able to scatter the material it encounters to highly-inclined orbits if the material is on an eccentric orbit. Such eccentric orbits can be the result of resonance trapping and eccentricity pumping. Simulations show that for a certain range of migration rates and planet masses, resonance capture combined with planetary migration indeed causes the planetesimals to reach eccentric orbits and subsequently get scattered to highly-inclined orbits. The size distribution of the resulting dust is calculated determined to find the total mass and optical depth, which are found to compare reasonably well with the observed structures. Conclusions. Dynamical scattering of planetesimals caused by a planet migrating in, followed by the grinding down of these planetesimals to dust grains, appears to be a promising explanation for the inferred circumstellar dust clouds. Further study is needed to see if the haloes can be used to infer the presence of planets.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell