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Detailed Reference Information
Esposito et al. 1980
Esposito, L.W., Dilley, J.P. and Fountain, J.W. (1980). Photometry and Polarimetry of Saturn’s Rings From Pioneer Saturn. Journal of Geophysical Research 85: doi: 10.1029/JA080i011p05948. issn: 0148-0227.

We present a profile of the average normal optical depth for Saturn's rings between 1.22 and 2.35 Rs. In the A and B rings, horizontal inhomogeneities make these values deceptive. A thinner component of the B ring with optical depth less than 0.08 covers 1/2% to 4% of its surface area. In the A ring the more transparent component has optical depth &tgr;S>0.10 and covers more than 7% of its area. These thinner parts of the rings would rarely be apparent from earth-based observations. The particles in the C ring are larger than 15&mgr; and different from those in the B and A rings. The C ring is either homogeneous with high albedo (in the red) ?0?0.75 and forward scattering phase functions or shows a gradient in albedo with distance from Saturn. In the latter case the red albedo ranges from ?0?0.3 at the inner edge of ring C to ?0?0.65 at the outer edge, and the phase function is both moderately forward and backward scattering. Polarimetry of Saturn's rings provide only an upper limit for the B ring polarization, p<15%, which is consistent with predictions from ground-based data. In the outer A ring, the polarization is negative p (blue)=-7¿2%; p (red)=-1¿2%. Azimuthal variations are seen on the darkside of the A ring with a peak-to-trough ratio of 1.25. The position angle of the maximum is close to that seen from earth. No variations are seen in the B and C rings with an upper limit of 6%. The measured color of the A ring supports the many particle thick model of Saturn's rings.

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Journal of Geophysical Research
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