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Saturn's moon Phoebe as a captured body from the outer Solar System
Torrence V Johnson1, Jonathan I Lunine
1Jet Propulsion Laboratory, California Institute of Technology, M/S 264-525 4800 Oak Grove Drive, Pasadena, California 91109, USA.
Nature
|May 6, 2005
Summary
Phoebe, a moon of Saturn, likely originated in the outer Solar System, not with the planet. Its composition matches Kuiper Belt objects, supporting its capture by Saturn.
Area of Science:
- Planetary Science
- Solar System Formation
- Astrogeology
Background:
- Phoebe, an irregular moon of Saturn, exhibits orbital characteristics suggesting capture rather than in-situ formation.
- Its surface composition resembles C-type asteroids and Kuiper Belt objects, differing from Saturn's regular moons.
Purpose of the Study:
- To test the hypothesis that Phoebe is a captured body from the outer Solar System.
- To determine Phoebe's origin by comparing its composition to solar nebula models.
Main Methods:
- Utilized data from the Cassini-Huygens spacecraft fly-by of Phoebe.
- Calculated Phoebe's rock-to-ice ratio using its density and measured solar abundances of oxygen and carbon.
Main Results:
- Phoebe's composition is similar to other solar nebula bodies like Triton and Pluto.
- Phoebe's composition significantly differs from the regular satellites of Saturn.
Conclusions:
- Phoebe's composition strongly supports its origin as a captured body from the outer Solar System.
- The findings reinforce the theory of planetary capture for irregular moons.
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