The topography of Janus

A topographic model of Saturn's larger co-orbital satellite Janus was derived from the shapes of limbs and terminators in Voyager images, modified locally to accommodate large craters and ridges. The model is presented here in tabular and graphic form, including the first detailed shaded relief maps of the satellite. The shape is approximated by a triaxial ellipsoid with axes of 196, 192 and 150 km. The volume is estimated to be 3.0 ± 0.5 × 10⁶ km³, leading to a density estimate of 0.67 ± 0.10 g/cm³. The surface is heavily cratered. Several possible crater chains of uncertain significance are observed, but few prominent linear ridges and no narrow grooves.