The angular width of the coherent back-scatter opposition effect: An application to icy outer planet satellites

It has been suggested recently that coherent back-scattering of light from powder-like regolithic surfaces can explain remarkable opposition brightening of some atmosphereless solar system bodies. In this paper, a dense-medium light-scattering theory is used to calculate the half-width at half-maximum (HWHM) of the coherent back-scattering peak for a number of scattering models. We demonstrate that HWHM strongly depends on the optical properties of the scattering medium and can serve as a critical test in comparing alternative models. It is shown that coherent back-scaterring may be a likely explanation of the opposition effect exhibited by icy outer planet satellites.