论文标题
湍流的尘埃捕获环作为行星形成的有效位点
Turbulent Dust-trapping Rings as Efficient Sites for Planetesimal Formation
论文作者
论文摘要
在亚MM中对原月球磁盘（PPD）的最新观察结果表明，环形下结构的无处不在，表明卵石大小的尘埃颗粒被困在湍流环状气压颠簸中。这种主要的范式转变还挑战了按流不稳定性从这种卵石中的行星形成的主要理论，该理论在压力梯度中起作用，可以通过湍流抑制。在这里，我们对尘埃捕获的粉尘捕获（包括灰尘反射，对灰尘诱捕）进行了三维局部剪切盒，非理想的磁性水力动力学（MHD）模拟。在磁化不稳定（MRI）产生的中等水平的湍流下，具有歧义性散射的磁化不稳定（MRI），适合于外盘条件，我们实现了通过湍流扩散平衡的尘埃捕获的准稳态状态。我们发现在气压最大值附近的所有模拟中都有强烈的灰尘块，达到了触发引力塌陷以形成行星的最大密度远高于阈值。强大的压力凸起将灰尘颗粒集中在凸起中心。由于压力较弱，由于灰尘的反射，灰尘还可以集中在凸起中心的次生丝中，但是强烈的团块仍然主要发生在颠簸中心周围的主环中。我们的结果揭示了尘埃夹环是外部PPD中行星形成的稳健位置，而它们可能具有多种观察特性。
Recent observations of protoplanetary disks (PPDs) in the sub-mm have revealed the ubiquity of annular substructures, indicative of pebble-sized dust particles trapped in turbulent ring-like gas pressure bumps. This major paradigm shift also challenges the leading theory of planetesimal formation from such pebbles by the streaming instability, which operates in a pressure gradient and can be suppressed by turbulence. Here we conduct three-dimensional local shearing-box, non-ideal magnetohydrodynamic (MHD) simulations of dust trapping in enforced gas pressure bumps including dust backreaction. Under the moderate level of turbulence generated by the magnetorotational instability (MRI) with ambipolar diffusion that is suitable for outer disk conditions, we achieve quasi-steady states of dust trapping balanced by turbulent diffusion. We find strong dust clumping in all simulations near the gas pressure maxima, reaching a maximum density well above the threshold of triggering gravitational collapse to form planetesimals. A strong pressure bump concentrates dust particles towards bump center. With a weak pressure bump, dust can also concentrate in secondary filaments off the bump center due to dust backreaction, but strong clumping still occurs mainly in the primary ring around the bump center. Our results reveal dust-trapping rings as robust locations for planetesimal formation in outer PPDs, while they may possess diverse observational properties.
