SURFACE TEXTURAL PROPERTIES OF ICY SATELLITES - A COMPARISON BETWEEN EUROPA AND RHEA

Solar phase curves for Rhea are presented using new telescopic opposit ion data along with Voyager imaging observations. Two viable solutions were found to Hapke's model (1986, Icarus 67, 264-280) which was used to describe this phase curve. The porosity derived from the model's o pposition parameters show that the optically active portion of Rhea's regolith has a porosity between 80 and 95%, which is slightly lower th an the porosity seen on Europa and higher than the porosity measured f or the Moon using similar methods. The macroscopic roughness is compar able to that measured by Verbiscer and Veverka (1989, Icarus 82, 336-3 53) far Rhea. The single-particle scattering functions found in this s tudy are predominantly forward scattering, which contradicts the resul ts of Verbiscer and Veverka (1989). (C) 1995 Academic Press, Inc.