Research Articles

High-Resolution Microwave Images of Saturn

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Science  15 Sep 1989:
Vol. 245, Issue 4923, pp. 1211-1215
DOI: 10.1126/science.245.4923.1211


An analysis of high-resolution microwave images of Saturn and Saturn's individual rings is presented. Radio interferometric observations of Saturn taken at the Very Large Array in New Mexico at wavelengths of 2 and 6 centimeters reveal interesting new features in both the atmosphere and rings. The resulting maps show an increase in brightness temperature of about 3 K from equator to pole at both wavelengths, while the 6-centimeter map shows a bright band at northern mid-latitudes. The data are consistent with a radiative transfer model of the atmosphere that constrains the well-mixed, fully saturated, NH3 mixing ratio to be 1.2 x 10-4 in a region just below the NH3 clouds, while the observed bright band indicates a 25 percent relative decrease of NH3 in northern mid-latitudes. Brightness temperatures for the classical rings are presented. Ring brightness shows a variation with azimuth and is linearly polarized at an average value of about 5 percent. The variations in ring polarization suggest that at least 20 percent of the ring brightness is the result of a single scattering process.

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