Estimates of the size of the particles in the rings of saturn and their cosmogonic implications |
| |
Authors: | James B Pollack Audrey Summers Betty Baldwin |
| |
Institution: | NASA Ames Research Center, Moffett Field, California 94035 USA |
| |
Abstract: | Very low values of the radio brightness temperature of the rings of Saturn indicate that their high refar reflectivity is not simply due to a gain effect in the backscattering direction. These two sets of observations are consistent with the ring particles having a very high single scattering albedo at radio wavelenghts, with multiple scattering effects being important. Comparison of scattering calculations for ice and silicate particles with the radio and radar observations imply a mean particle radius of ~1 cm. The ice bands observed in the rings' near-infrared reflectivity spectra are formed by scattering within a microstructure on the surface of the ring particles, with the scattering centers being 25–125 μm in size. The Poynting-Robertson effect has caused a significant spiraling-in of the ring particles, probably resulting in a broadening of the rings. The inferred mean size is consistent with a model in which meteoroid impacts have caused a substantial reduction in the mean particle size from its initial value. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |