Planetesimal formation at the gas pressure bump following a migrating planet
Planetesimal formation at the gas pressure bump following a migrating planet
复制标题
行星迁移后气体压力凸起处的星子形成
DOI：
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发表时间：
2020
影响因子：
6.5
通讯作者：
Y. Alibert
中科院分区：
文献类型：
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作者：
Yuhito Shibaike;Y. Alibert
上下文人们提出了许多设想，以避免已知的困难，在星子形成，如漂移或碎片障碍。然而，在这些情况下，星子一般只在原行星盘的某些特定位置形成。另一方面，在行星形成模型和星群合成模型中，一般假设星子广泛分布在原行星盘中。
目标。我们提出了一个新的方案，其中星子可以形成在这些光盘的广泛领域。微行星形成于第一代行星形成的气体压力凸起处（例如由卵石吸积形成），并且随着行星的迁移，形成区域在圆盘中向内扩展。
方法.我们使用一个简单的一维拉格朗日粒子模型来计算由一个迁移的嵌入式行星扰动的气体盘中的卵石的径向分布。我们认为，星子形成的流动不稳定性的点，卵石与气体的密度比的中平面变得大于1。在这项工作中，我们固定了鹅卵石的斯托克斯数和行星的质量，以研究这种新情况的基本特征。我们还研究了一些关键参数，如气体盘模型，卵石质量通量，行星的迁移速度，湍流强度的影响。
结果我们发现，只要卵石流是典型的，湍流不是太强，星子形成在原行星盘的广泛地区。星子表面密度取决于卵石质量通量和行星的迁移速度。星子的总质量和形成区的轨道位置强烈地依赖于卵石质量通量。我们还发现，轮廓的星子表面密度和它的斜率可以估计由非常简单的方程。
结论.我们表明，我们的新方案可以解释形成的星子在广泛的领域。我们对小行星表面密度分布提供的简单估计可以用作种群合成模型的初始条件。
Context. Many scenarios have been proposed to avoid known difficulties in planetesimal formation such as drift or fragmentation barriers. However, in these scenarios planetesimals in general only form at some specific locations in protoplanetary discs. On the other hand, it is generally assumed in planet formation models and population synthesis models that planetesimals are broadly distributed in the protoplanetary disc.
Aims. We propose a new scenario in which planetesimals can form in broad areas of these discs. Planetesimals form at the gas pressure bump formed by a first-generation planet (e.g. formed by pebble accretion) and the formation region spreads inward in the disc as the planet migrates.
Methods. We used a simple 1D Lagrangian particle model to calculate the radial distribution of pebbles in the gas disc perturbed by a migrating embedded planet. We consider that planetesimals form by streaming instability at the points where the pebble-to-gas density ratio on the mid-plane becomes larger than unity. In this work, we fixed the Stokes number of pebbles and the mass of the planet to study the basic characteristics of this new scenario. We also studied the effect of some key parameters, such as the gas disc model, the pebble mass flux, the migration speed of the planet, and the strength of turbulence.
Results. We find that planetesimals form in wide areas of protoplanetary discs provided the flux of pebbles is typical and the turbulence is not too strong. The planetesimal surface density depends on the pebble mass flux and the migration speed of the planet. The total mass of the planetesimals and the orbital position of the formation area strongly depend on the pebble mass flux. We also find that the profile of the planetesimal surface density and its slope can be estimated by very simple equations.
Conclusions. We show that our new scenario can explain the formation of planetesimals in broad areas. The simple estimates we provide for the planetesimal surface density profile can be used as initial conditions for population synthesis models.
影响因子：
64.8
作者：
D. Segura-Cox;A. Schmiedeke;J. Pineda;I. Stephens;M. Fern'andez-L'opez;L. Looney;P. Caselli;
通讯作者：
D. Segura-Cox;A. Schmiedeke;J. Pineda;I. Stephens;M. Fern'andez-L'opez;L. Looney;P. Caselli;