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Small particles dominate Saturn's Phoebe ring to surprisingly large distances
Douglas P Hamilton1, Michael F Skrutskie2, Anne J Verbiscer2
1Department of Astronomy, University of Maryland, College Park, Maryland 20742-2421, USA.
Nature
|June 12, 2015
Summary
Saturn's outermost Phoebe ring extends much farther than previously known, from 100 to 270 Saturn radii. Analysis suggests steep particle size distributions and larger particles dominate this faint, ancient ring system.
Area of Science:
- Planetary Science
- Astronomy
- Ring Systems
Background:
- Saturn's outermost ring, discovered in 2009, originates from the moon Phoebe.
- The ring's full radial extent and particle sizes were previously undetermined.
- It is significantly larger than Saturn's E ring.
Purpose of the Study:
- To determine the complete radial extent of Saturn's Phoebe ring.
- To constrain the particle size distribution within the ring.
- To understand the ring's formation and evolution.
Main Methods:
- Infrared imaging to map the entire ring.
- Modeling of orbital dynamics for ring particles ejected from Phoebe.
- Construction of theoretical power-law profiles for particle size distribution.
Main Results:
- The Phoebe ring extends from 100 to 270 Saturn radii.
- Steep particle size distribution profiles best fit observational data.
- Elevated grain temperatures likely contribute to the observed steepness.
Conclusions:
- Saturn's Phoebe ring is a vast structure with a steep particle size distribution.
- Larger particles (radii > 10 cm) contribute significantly to the ring's cross-sectional area.
- These larger particles have stable orbits, indicating long-term persistence.
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