Size distribution of particles in Saturn’s rings from aggregation and fragmentation
- Nikolai Brilliantova,
- P. L. Krapivskyb,
- Anna Bodrovac,d,
- Frank Spahnd,
- Hisao Hayakawae,
- Vladimir Stadnichukc, and
- Jürgen Schmidtf,1
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Edited by Neta A. Bahcall, Princeton University, Princeton, NJ, and approved June 12, 2015 (received for review February 26, 2015)
Significance
Although it is well accepted that the particle size distribution in Saturn’s rings is not primordial, it remains unclear whether the observed distribution is unique or universal, that is, whether it is determined by the history of the rings and details of the particle interaction or whether the distribution is generic for all planetary rings. We show that a power-law size distribution with large-size cutoff, as observed in Saturn’s rings, is universal for systems where a balance between aggregation and disruptive collisions is steadily sustained. Hence, the same size distribution is expected for any ring system where collisions play a role, like the Uranian rings, the recently discovered rings of Chariklo and Chiron, and possibly rings around extrasolar objects.
Abstract
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,
Footnotes
- ↵1To whom correspondence should be addressed. Email: jurgen.a.schmidt@oulu.fi.
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Author contributions: N.B. designed research; N.B., P.L.K., A.B., H.H., V.S., and J.S. performed research; N.B., P.L.K., A.B., H.H., V.S., and J.S. contributed new reagents/analytic tools; N.B., P.L.K., A.B., V.S., and J.S. analyzed data; and N.B., P.L.K., F.S., and J.S. wrote the paper.
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The authors declare no conflict of interest.
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This article is a PNAS Direct Submission.
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This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1503957112/-/DCSupplemental.