Thermal emission of spherical spinning ring particles

The standard model

Laboratoire AIM, Unité Mixte de Recherche No. 7158 CEA-CNRS-Université Paris 7, Denis Diderot, France e-mail: cferrari@cea.fr, leyratc@discovery.saclay.cea.fr

Received: 1 March 2005
Accepted: 20 September 2005

Abstract

A simple new thermal model was developed to study the effects of the spherical shape of ring particles, of their finite thermal inertia, and of their spinning properties on the rings thermal emission. Ring particles are assumed to be scattered in a monolayer, a structure that might exist at least in the population of large particles embedded in Saturn's A and C rings. Their spin rates and obliquities are either identical or randomly distributed, but are constant with time. It is found that the infrared radiation from Saturn on spherical particles generates large azimuthal temperature asymmetries along the ring. Their amplitude and overall shape mainly depend on the viewing geometry, the spin properties, and the thermal inertia.