Micrometer-sized ice particles for planetary-science experiments - II. Bidirectional reflectance

摘要: Abstract We have measured the bidirectional reflectance of spherical micrometer-sized water–ice particles in visible spectral range over a wide incidence and emission angles. The small ice spheres were produced by spraying fine water droplets directly into liquid nitrogen. resulting mean particle radii are 1.47 + 0.96 − 0.58 μm. Such material shares many properties with comets at surface icy satellites. Measurements show that fresh sample is highly backscattering, contrasting natural terrestrial snow frost. formation agglomerates during production results noticeable variability photometric samples their initial state. also observed significant temporal evolutions scattering behavior samples, shifting towards more forward within some tens hours, most likely from sintering processes. All data fitted Hapke model (1993 2002 formulation) one/two/three-parameter Henyey–Greenstein phase function parameters provided. These can be used to compare laboratory behaviors astronomical objects. show, particular, optical reproduce predominant backscattering curves Enceladus Europa.