Size distribution of particles in Saturn's rings from aggregation and fragmentation
Size distribution of particles in Saturn's rings from aggregation and fragmentation
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DOI：
10.1073/pnas.1503957112
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发表时间：
2015-08-04
影响因子：
11.1
通讯作者：
Schmidt, Jurgen
中科院分区：
文献类型：
--
作者：
Brilliantov, Nikolai;Krapivsky, P. L.;Schmidt, Jurgen
土星环由大量的水冰粒子和少量的岩石物质组成。由于角动量守恒和耗散粒子间碰撞中能量的稳定损失的相互作用，它们形成了一个平坦的圆盘。对于大小从几厘米到几米的粒子，可以推导出半径的幂律分布，类似于r(-q)，其中q近似于3；对于较大的尺寸，分布有一个陡峭的截止点。有人认为，这种尺寸分布可能是由环状颗粒的聚集和破碎之间的平衡引起的，但幂律依赖性和上尺寸截止值都没有建立在理论基础上。在这里，我们提出了一个粒度分布的模型，定量地解释了观察结果。根据数据，我们的模型预测指数q被限制在区间2.75
Saturn's rings consist of a huge number of water ice particles, with a tiny addition of rocky material. They form a flat disk, as the result of an interplay of angular momentum conservation and the steady loss of energy in dissipative interparticle collisions. For particles in the size range from a few centimeters to a few meters, a power-law distribution of radii, similar to r(-q) with q approximate to 3, has been inferred; for larger sizes, the distribution has a steep cutoff. It has been suggested that this size distribution may arise from a balance between aggregation and fragmentation of ring particles, yet neither the power-law dependence nor the upper size cutoff have been established on theoretical grounds. Here we propose a model for the particle size distribution that quantitatively explains the observations. In accordance with data, our model predicts the exponent q to be constrained to the interval 2.75