Abstract.
The Cassini Composite Infrared Spectrometer (CIRS) spatially resolved Saturn’s main rings in the far-infrared, measuring the spectrum from 20 to 400 wavenumbers (cm−1) (tens of microns to submillimeter wavelengths). We find a spectral roll-off below 50 cm−1 (200 μm) for each of the A, B and C rings. From these data we derive temperatures and emissivities for each ring. Mie calculations of individual water ice particles show a natural variation in the optical properties of the rings similar to the roll-off we observe in our data. A simple radiative transfer model placing a distribution of water ice particles randomly in a layer provides a good fit to the data and illustrates one possible interpretation of the results. This is most likely only part of the explanation for the roll-off effect as the impact of shape, surface, and composition variations have been left for future analysis.
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Acknowledgements
The authors would like to thank Paul Romani, Richard Achterberg, and Conor Nixon for their help designing and planning the CIRS ring observations. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
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SPILKER, L.J., PILORZ, S.H., EDGINGTON, S.G. et al. CASSINI CIRS OBSERVATIONS OF A ROLL-OFF IN SATURN RING SPECTRA AT SUBMILLIMETER WAVELENGTHS. Earth Moon Planet 96, 149–163 (2005). https://doi.org/10.1007/s11038-005-9060-8
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DOI: https://doi.org/10.1007/s11038-005-9060-8