Changes in orientation and shape of protoplanetary discs moving through an ambient medium
Changes in orientation and shape of protoplanetary discs moving through an ambient medium
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原行星盘在环境介质中移动时方向和形状的变化
DOI：
--
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
S. Zwart
中科院分区：
文献类型：
--
作者：
T. Wijnen;F. I. Pelupessy;O. Pols;S. Zwart
在我们的太阳系、凌日系外行星和碎片盘的轨道平面中，都观察到了行星轨道平面与其宿主恒星赤道平面之间的错位。我们提出了一种机制，导致这样的自旋轨道错位的原行星盘，由于其通过周围介质的运动。我们的物理解释的机制是基于斯塔克问题的理论解。我们测试这个想法进行自洽流体动力学模拟和简化的重力$N$体模拟。$N$-body模型将该机制简化为相关的物理过程。流体动力学模拟显示的机制，在其全部范围内，包括气体动力学和粘性过程中的光盘，不包括在理论框架。我们发现，嵌入流的原行星盘改变其方向，因为它的角动量矢量往往平行于相对速度矢量对齐。由于流体所施加的力，圆盘中的轨道变得偏心，这产生净扭矩，从而改变轨道倾角。圆盘的倾斜使它收缩。除了变得不平衡之外，即使倾斜度基本上没有变化，气体盘也形成螺旋臂。这一过程在高速度下最为有效，因此观测信号预计大多出现在大质量恒星形成区和恒星风或超新星喷出物周围。我们的$N$体模型表明，与超新星喷出物的相互作用是一个可行的解释，在我们的太阳系中观察到的自旋轨道不一致。
Misalignments between the orbital planes of planets and the equatorial planes of their host stars have been observed in our solar system, in transiting exoplanets, and in the orbital planes of debris discs. We present a mechanism that causes such a spin-orbit misalignment for a protoplanetary disc due to its movement through an ambient medium. Our physical explanation of the mechanism is based on the theoretical solutions to the Stark problem. We test this idea by performing self-consistent hydrodynamical simulations and simplified gravitational $N$-body simulations. The $N$-body model reduces the mechanism to the relevant physical processes. The hydrodynamical simulations show the mechanism in its full extent, including gas-dynamical and viscous processes in the disc which are not included in the theoretical framework. We find that a protoplanetary disc embedded in a flow changes its orientation as its angular momentum vector tends to align parallel to the relative velocity vector. Due to the force exerted by the flow, orbits in the disc become eccentric, which produces a net torque and consequentially changes the orbital inclination. The tilting of the disc causes it to contract. Apart from becoming lopsided, the gaseous disc also forms a spiral arm even if the inclination does not change substantially. The process is most effective at high velocities and observational signatures are therefore mostly expected in massive star-forming regions and around winds or supernova ejecta. Our $N$-body model indicates that the interaction with supernova ejecta is a viable explanation for the observed spin-orbit misalignment in our solar system.
DOI：
10.1146/annurev-astro-081811-125523
发表时间：
2012-03
影响因子：
33.3
作者：
W. Kley;R. Nelson
通讯作者：
W. Kley;R. Nelson
混沌恒星的形成以及恒星旋转与盘和行星轨道轴的对齐
DOI：
10.1111/j.1365-2966.2009.15773.x
发表时间：
2010
影响因子：
4.8
作者：
Bate M
通讯作者：
Bate M