论文标题
形成行星的气体信封中的组成湍流和分层
Compositional Turbulence and Layering in the Gaseous Envelopes of Forming Planets
论文作者
论文摘要
粉尘晶粒的差分沉降和生长会影响地形过程中气态行星辐射信封的结构。足够快速的尘埃生长会导致信封具有大幅度降低的辐射运输的粘液性，从而促进了行星形成。我们重新审视了这个问题，并确定尘埃沉淀和谷物的生长也导致外部行星信封，由于其倒数平均分子重量梯度，这些信封容易发生组成不稳定性。在各种条件下，我们发现形成行星的辐射信封经历了由半透明版本的hyterohaline不稳定性（“指法对流”）驱动的组成湍流。构图的湍流似乎有效地在超级AU距离（例如$ 5 $ au）的辐射行星中混合灰尘，但在Sub-Au距离（例如0.2 $ au）中并非如此。我们还解决了在这种情况下构图分层的可能性。在Sub-Au与Super-Au距离生长的行星信封的独特动荡政权可能会在最终的行星上留下烙印。
Differential settling and growth of dust grains impact the structure of the radiative envelopes of gaseous planets during formation. Sufficiently rapid dust growth can result in envelopes with substantially reduced opacities for radiation transport, thereby facilitating planet formation. We revisit the problem and establish that dust settling and grain growth also lead to outer planetary envelopes that are prone to compositional instabilities, by virtue of their inverted mean-molecular weight gradients. Under a variety of conditions, we find that the radiative envelopes of forming planets experience compositional turbulence driven by a semi-transparent version of the thermohaline instability ('fingering convection'). The compositional turbulence seems efficient at mixing dust in the radiative envelopes of planets forming at super-AU distances (say $5$ AU) from a Sun-like star, but not so at sub-AU distances (say $0.2$ AU). We also address the possibility of compositional layering in this context. Distinct turbulent regimes for planetary envelopes growing at sub-AU vs. super-AU distances could leave an imprint on the final planets formed.
