论文标题
径向漂移的灰尘清除在不断发展的原球盘中
Dust clearing by radial drift in evolving protoplanetary discs
论文作者
论文摘要
最近的调查显示，原球盘通常具有灰尘块，似乎不足以说明系外行星系统的高发生率。我们证明，这种观察到的尘埃耗竭与卵石的径向漂移一致。使用蒙特卡洛法，我们使用一维数值方法模拟了一组原星盘的演变，以粘着每个气盘，以及尘埃颗粒的径向漂移，这些粉尘颗粒的大小增长到100 $ $ m $ m。对于2 Myr旧的星星，我们发现气盘质量和气盘质量之间的略微尺度缩放率（$ M_ \ Mathrm {G} \ Propto \ dot \ dot \ dot {M}^{0.9} $）。但是，对于尘埃质量，我们发现进化的灰尘盘的缩放率较弱，而气体吸积率则取决于簇的年龄，并取决于簇的年龄以及群集中圆盘的内在年龄扩散。最终，我们发现，原月光盘中存在的尘埃质量是1-3 Myr旧星形成区域中的10-100泥土质量，而原始灰尘预算中耗尽了10到100倍。随着灰尘从外盘排出，卵石堆积在内盘中，并在局部将灰尘与气体比率提高高达最初值4。在这些高尘埃与气体比率的区域中，我们发现通过流媒体不稳定性和随后通过卵石积聚的增长而形成行星的条件。我们还发现以下与恒星质量的缩放关系在1-2个Myr旧群集中：气体吸积率和恒星质量之间的超级线性缩放（$ \ dot {M} \ propto m_ \ star^{1.4} $），在气盘质量和stellar质量质量之间有点超级线性的缩放（ m_ \ star^{1.4} $）和灰尘盘质量和恒星质量之间的超级线性关系（$ m_ \ mathrm {d} \ propto m_ \ star^{1.4-4.1} $）。
Recent surveys have revealed that protoplanetary discs typically have dust masses that appear to be insufficient to account for the high occurrence rate of exoplanet systems. We demonstrate that this observed dust depletion is consistent with the radial drift of pebbles. Using a Monte Carlo method we simulate the evolution of a cluster of protoplanetary discs, using a 1D numerical method to viscously evolve each gas disc together with the radial drift of dust particles that have grown to 100 $μ$m in size. For a 2 Myr old cluster of stars, we find a slightly sub-linear scaling between the gas disc mass and the gas accretion rate ($M_\mathrm{g}\propto\dot{M}^{0.9}$). However, for the dust mass we find that evolved dust discs have a much weaker scaling with the gas accretion rate, with the precise scaling depending on the age at which the cluster is sampled and the intrinsic age spread of the discs in the cluster. Ultimately, we find that the dust mass present in protoplanetary disc is on the order of 10-100 Earth masses in 1-3 Myr old star-forming regions, a factor of 10 to 100 depleted from the original dust budget. As the dust drains from the outer disc, pebbles pile up in the inner disc and locally increase the dust-to-gas ratio by a factor of up to 4 above the initial value. In these high dust-to-gas ratio regions we find conditions that are favourable for planetesimal formation via the streaming instability and subsequent growth by pebble accretion. We also find the following scaling relations with stellar mass within a 1-2 Myr old cluster: a slightly super-linear scaling between the gas accretion rate and stellar mass ($\dot{M}\propto M_\star^{1.4}$), a slightly super-linear scaling between the gas disc mass and the stellar mass ($M_\mathrm{g}\propto M_\star^{1.4}$) and a super-linear relation between the dust disc mass and stellar mass ($M_\mathrm{d}\propto M_\star^{1.4-4.1}$).
