A Lagrangian model for dust evolution in protoplanetary disks: formation of wet and dry planetesimals at different stellar masses
A Lagrangian model for dust evolution in protoplanetary disks: formation of wet and dry planetesimals at different stellar masses
复制标题
原行星盘中尘埃演化的拉格朗日模型：不同恒星质量下湿和干星子的形成
DOI：
10.1051/0004-6361/201834047
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发表时间：
2018
影响因子：
6.5
通讯作者：
S. Krijt
中科院分区：
文献类型：
--
作者：
D. Schoonenberg;C. Ormel;S. Krijt
我们引入了一种新的拉格朗日光滑粒子方法来模拟原行星盘中卵石的生长和漂移。该模型的拉格朗日性质使其特别适合于跟踪单个（组）粒子的特性，例如它们的组成。在这项工作中，我们专注于固体颗粒的水含量。通过流动不稳定性的星子形成被考虑在内，部分是基于以前的结果外的水雪线，在最近的出版物中提出的流动不稳定性。我们验证了我们的模型，从文献中复制早期的结果，并将我们的模型应用到不同质量的恒星周围的稳态粘性气体盘（具有恒定的气体吸积率）。我们还提出了各种其他模型，我们探讨卵石吸积的影响，破碎速度阈值，磁盘的全球金属丰度，和随时间变化的气体吸积率。我们发现，星子优先形成在水雪线外的局部环，在早期的磁盘的寿命（105年），当卵石质量通量高到足以触发流不稳定。在行星形成过程的第一阶段，雪线的位置几乎没有变化，由于缓慢的粘性演变，我们的结论是，假设一个恒定的气体吸积率是合理的，在这第一阶段。将圆盘的固体储存器转化为星子的效率取决于水雪线的位置。在水雪线离星星较远的地方，温度较低的圆盘与较近的水雪线在产生星子方面比温度较高的圆盘更有效。因此，低质量恒星倾向于更有效地形成星子，但任何相关性都可能被盘属性的差异所掩盖。
We introduce a new Lagrangian smooth-particle method to model the growth and drift of pebbles in protoplanetary disks. The Lagrangian nature of the model makes it especially suited to following characteristics of individual (groups of) particles, such as their composition. In this work we focus on the water content of solid particles. Planetesimal formation via streaming instability is taken into account, partly based on previous results on streaming instability outside the water snowline that were presented in a recent publication. We validated our model by reproducing earlier results from the literature and apply our model to steady-state viscous gas disks (with constant gas accretion rate) around stars with different masses. We also present various other models where we explore the effects of pebble accretion, the fragmentation velocity threshold, the global metallicity of the disk, and a time-dependent gas accretion rate. We find that planetesimals preferentially form in a local annulus outside the water snowline, at early times in the lifetime of the disk (≲105 yr), when the pebble mass fluxes are high enough to trigger the streaming instability. During this first phase in the planet formation process, the snowline location hardly changes due to slow viscous evolution, and we conclude that assuming a constant gas accretion rate is justified in this first stage. The efficiency of converting the solids reservoir of the disk to planetesimals depends on the location of the water snowline. Cooler disks with a closer-in water snowline are more efficient at producing planetesimals than hotter disks where the water snowline is located further away from the star. Therefore, low-mass stars tend to form planetesimals more efficiently, but any correlation may be overshadowed by the spread in disk properties.