| Autor: |
Brilliantov, Nikolai, Krapivsky, Pavel, Bodrova, Anna, Spahn, Frank, Hayakawa, Hisao, Stadnichuk, Vladimir, Schmidt, Juergen |
| Rok vydání: |
2013 |
| Předmět: |
|
| Zdroj: |
PNAS 2015 112 (31) 9536-9541 |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1073/pnas.1503957112 |
| Popis: |
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 inter-particle collisions. For particles in the size range from a few centimeters to a few meters, a power-law distribution of radii, $\sim r^{-q}$ with $q \approx 3$, 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 $2.75 \le q \le 3.5$. Also an exponential cutoff for larger particle sizes establishes naturally with the cutoff-radius being set by the relative frequency of aggregating and disruptive collisions. This cutoff is much smaller than the typical scale of micro-structures seen in Saturn's rings. |
| Databáze: |
arXiv |
| Externí odkaz: |
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