Thermal response of Iapetus to an eclipse by Saturn's rings
Nicholson, P. D.; Matthews, K.; Soifer, B. T.; Neugebauer, G.; Beckwith, S. V. W.; Gatley, I.
United States
Abstract
Measurements of Iapetus as seen at 20 and 2.2 μm in the shadow of Saturn's ring are given, providing the thermal response to a rapidly varying heat input. The 20 μm thermal emission follows the 2.2 μm flux input closely. The observations, plus a simple diffusion calculation, imply that the surface of Iapetus is made of material having a very small thermal inertia, probably I≲10JmsK.