论文标题
偏心圆盘的流体动力动力及其对环境行星原位形成的影响
Hydrodynamical turbulence in eccentric circumbinary discs and its impact on the in situ formation of circumbinary planets
论文作者
论文摘要
偏心的气态盘是不稳定的参数不稳定性，涉及惯性 - 重力波与盘中的偏心模式之间的谐振相互作用。我们提出了形成内部空腔的无粘性电圆盘的3D全局流体动力学模拟，并通过与中央二进制的相互作用而变得偏心。参数不稳定性会增长并生成湍流，该湍流在距离$ \ lyseSim 7 \; a_ {bin} $的情况下，用应力参数$α\ sim 5 \ sim 5 \ sim 5 \ sim 5 \ sim \ sim 5 \ times 10^{ - 3} $，其中$ a_ {bin} $是bin {bin} $。垂直湍流扩散以对应于$α_{diff} \ sim 1-2 \ times 10^{ - 3} $的速率发生。我们检查了湍流扩散对卵石垂直沉降的影响，以及嵌入的行星卵石积聚的速率。在稳定状态下，带有stokes数字的灰尘颗粒$ {\ it st} \ Lessim 0.1 $形成有限厚度$ H_D \ gtrsim 0.1 H $ 0.1 H $，其中$ h $是气体尺度的高度。然后，与层状光盘中的速率相比，卵子积聚效率降低了$ r_ {acc}/h_d $的因子$ r_ {acc}/h_d $。用$ m_p \ lyssim 0.1 \; m_ \ oplus $，对于$ {\ it st} \ gtrsim 0.5 $的粒子的卵石积聚也减少了，这也是由于湍流引起的速度踢。这些效果结合在一起，使Ceres质量物体生长到卵石隔离质量所需的时间，比典型的碟寿命更长。因此，正如开普勒任务所发现的那样，很难使用一种原位模型来解释，从而使流媒体不稳定性和卵石积聚的结合使用，这是很难解释的。
Eccentric gaseous discs are unstable to a parametric instability involving the resonant interaction between inertial-gravity waves and the eccentric mode in the disc. We present 3D global hydrodynamical simulations of inviscid circumbinary discs that form an inner cavity and become eccentric through interaction with the central binary. The parametric instability grows and generates turbulence that transports angular momentum with stress parameter $α\sim 5 \times 10^{-3}$ at distances $\lesssim 7 \;a_{bin} $, where $a_{bin}$ is the binary semi-major axis. Vertical turbulent diffusion occurs at a rate corresponding to $α_{diff}\sim 1-2\times 10^{-3}$. We examine the impact of turbulent diffusion on the vertical settling of pebbles, and on the rate of pebble accretion by embedded planets. In steady state, dust particles with Stokes numbers ${\it St} \lesssim 0.1$ form a layer of finite thickness $H_d \gtrsim 0.1 H$, where $H$ is the gas scale height. Pebble accretion efficiency is then reduced by a factor $r_{acc}/H_d$, where $r_{acc}$ is the accretion radius, compared to the rate in a laminar disc. For accreting core masses with $m_p \lesssim 0.1\; M_\oplus$, pebble accretion for particles with ${\it St} \gtrsim 0.5$ is also reduced because of velocity kicks induced by the turbulence. These effects combine to make the time needed by a Ceres-mass object to grow to the pebble isolation mass, when significant gas accretion can occur, longer than typical disc lifetimes. Hence, the origins of circumbinary planets orbiting close to their central binary systems, as discovered by the Kepler mission, are difficult to explain using an in situ model that invokes a combination of the streaming instability and pebble accretion.
