Planetary science: Examining Saturn’s
‘new’ ring *IMAGES*
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NATURE
Embargo
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London: Wednesday 10 June 2015 18:00 (BST)
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New York: Wednesday 10 June 2015 13:00 (EDT)
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Tokyo: Thursday 11 June 2015 02:00 (JST)
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Sydney: Thursday 11 June 2015 03:00 (AEST)
Saturn’s outermost ring is mainly made up of very small dust particles, with a seemingly unusual
distribution of particle sizes compared with elsewhere in the Solar system, a study in this week’s
Nature finds. New observations of this ring provide a detailed view of the full disk and enable the
structure and composition of the ring to be determined, which may give clues about how the ring
formed.
Saturn’s farthest faint ring, discovered in 2009,is probably formed from particles ejected from the
distant moon Phoebe. Its total radial extent or particle sizes could not be measured from the
initial observations, but Douglas Hamilton and colleagues use new images from NASA’s WISE
spacecraft to paint a detailed picture of this ring. They show that the ring spans a region of sky
over 500 times the size of Saturn and is over ten times larger than Saturn’s E ring. The authors
find that small particles dominate the ring, whereas rocks that are soccer-ball-sized or larger (at
least 10 cm) only make up a small fraction of this ring. Although this particle size distribution is
unusual in the Solar System, they may reflect particle-formation processes that have not
previously been considered, the authors conclude.
Article and author details
1. Small particles dominate Saturn's Phoebe ring to surprisingly
large distances
Corresponding Author
Douglas Hamilton
University of Maryland, College Park, Maryland, United States
Email: dphamil@umd.edu, Tel: +1 301 405 1548
DOI
10.1038/nature14476
Online paper*
http://nature.com/articles/doi:10.1038/nature14476
* Please link to the article in online versions of your report (the URL will go live after the embargo ends).
Geographical listings of authors
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United States
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Image 1
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Caption: An artists' conception of how Saturn's immense Phoebe ring might appear to eyes sensitive to
the infrared wavelengths at which the ring was discovered. A vast and diffuse annulus of dusty material
surrounds tiny Saturn and is set against a background starfield lit by faint nebular luminosity.
Credit: NASA/JPL/Space Science Institute
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Downloads: Low resolution (674.60 KB) or High resolution (833.16 KB)
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Image 2
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Caption: The 2009 discovery image of Saturn's dusty Phoebe ring (inset with orange tones) is overlain
on the tan rectangular ring extrapolated from both the data and theoretical expectations. The Phoebe
ring dwarfs, and is tilted relative to, Saturn's main ring.
Credit: NASA/JPL/U. Virginia
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Downloads: Low resolution (258.70 KB) or High resolution (258.70 KB)
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Image 3
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Caption: This graphic shows the intricate relationships between Saturn's immense ring, its source
satellite Phoebe, and the embedded satellite Iapetus. The dark face of Iapetus always leads its motion
and, like a car's windshield, collects all of the debris in its path.
Credit: NASA/JPL/Space Science Institute.
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Downloads: Low resolution (428.45 KB) or High resolution (428.45 KB)