A bolometric Bond albedo map of Iapetus: Observations from Cassini VIMS and ISS and Voyager ISS

Abstract

We utilized Cassini VIMS, Cassini ISS, and Voyager ISS observations of Iapetus to produce the first bolometric Bond albedo map of Iapetus. The average albedo values for the leading and trailing hemispheres are 0.06 ± 0.01 and 0.25 ± 0.03, respectively. However, the bright material in high-resolution ISS images has a value of 0.38 ± 0.04, highlighting the importance of resolution in determining accurate albedo values for Iapetus due to the speckling of localized regions of dark material into the trailing hemisphere. The practical application of this map is determining more accurate surface temperatures in thermal models; these albedo values translate into first order blackbody temperatures of 125.5 K and 118.4 K for the trailing and leading hemispheres at the semi-major axis.