Thermal cycles of a surface element located at the center of the leading hemisphere of Dione. The bolometric Bond albedo A is assumed 0.63 (Pitman et al. 2010). (a) The thermal conductivity is constant k_E0 = 0.001 W m⁻¹ K⁻¹ and the grain size, R, varies between 0.2 μm and 2 cm, assuming a porosity of p = 0.3 (solid line) or 0.8 (dash-dot line). The ice phase is amorphous. The resulting thermal inertia range between 10 and 20 MKS. (b) Both radiative and solid conductions through loose contacts are assumed here. The grain size, R, varies between 0.2 μm and 2 cm and the ice phase is either crystalline (Ih, solid line) or amorphous (Am, dash line) ice phase. The porosity is p = 0.5.