论文标题
随着颗粒的生长，漂移和蒸发前线的全球模型。 ii。孔隙度对固体进化的影响
Global Modeling of Nebulae With Particle Growth, Drift, and Evaporation Fronts. II. The Influence of Porosity on Solids Evolution
论文作者
论文摘要
湍流原球星云中的颗粒生长受到减慢或失速生长的障碍的组合的限制。此外，足以使气体脱离的颗粒会受到内向径向漂移的影响，这可能会导致大多数磁盘固体的耗尽，然后才能形成行星。紧凑的颗粒生长可能是不现实的。相反，由于分形骨料可能会克服这种所谓的径向漂移屏障，因此晶粒的生长更有可能，因为它们与气体相比，它们与气体相比更与气体耦合。我们在一系列湍流强度$α_ {\ rm {t}} = 10^{ - 5} -10^{ - 2} $中对粘性太阳状的星云进行建模分形骨料生长和压实。我们确实发现径向漂移对多孔聚集体的影响较小。但是，水雪线的分形骨料可以比紧凑型颗粒更快地生长到更大的块状质量，从而导致速度快速向内径向漂移。结果，雪地线以外的磁盘固体到$ \ sim 10-20 $ au比紧凑的增长模型早已耗尽，但是在$ \ sim 20 $ \ sim 20 $ au材料之外的材料保留了更长的时间，因为总数最初仍较低。然而，我们得出的结论即使是分形模型也会失去大多数磁盘固体，而没有某种Leap-Frog行星形成机制（例如流式的不稳定性（SI））的干预，尽管SI的条件通常永远无法满足，但短期阶段的短期阶段是$ \ sim 0.2 $ able sim 0.2 $ a snowline the Snowline of Snowline的短暂阶段，$α____________________________________________________________}
Incremental particle growth in turbulent protoplanetary nebulae is limited by a combination of barriers that can slow or stall growth. Moreover, particles that grow massive enough to decouple from the gas are subject to inward radial drift which could lead to the depletion of most disk solids before planetesimals can form. Compact particle growth is probably not realistic. Rather, it is more likely that grains grow as fractal aggregates which may overcome this so-called radial drift barrier because they remain more coupled to the gas than compact particles of equal mass. We model fractal aggregate growth and compaction in a viscously evolving solar-like nebula for a range of turbulent intensities $α_{\rm{t}} = 10^{-5}-10^{-2}$. We do find that radial drift is less influential for porous aggregates over much of their growth phase; however, outside the water snowline fractal aggregates can grow to much larger masses with larger Stokes numbers more quickly than compact particles, leading to rapid inward radial drift. As a result, disk solids outside the snowline out to $\sim 10-20$ AU are depleted earlier than in compact growth models, but outside $\sim 20$ AU material is retained much longer because aggregate Stokes numbers there remain lower initially. Nevertheless, we conclude even fractal models will lose most disk solids without the intervention of some leap-frog planetesimal forming mechanism such as the Streaming Instability (SI), though conditions for the SI are generally never satisfied, except for a brief period %for a brief stage around $\sim 0.2$ Myr at the snowline for $α_{\rm{t}}=10^{-5}$.
