A&A 441, 379-389 (2005)
Imaging Saturn's rings with CAMIRAS: thermal inertia of B and C ringsC. Ferrari1, P. Galdemard1, P. O. Lagage1, E. Pantin1 and C. Quoirin2
1 Laboratoire AIM, Unité Mixte de Recherche No. 7158 CEA-CNRS-Université Paris 7, France
2 Université Paris 6 - Pierre et Marie Curie, France
(Received 21 March 2005 / Accepted 11 May 2005)
Thermal inertias of Saturn's B and C ring particles have been derived from infrared observations using the CAMIRAS camera mounted on the Canada-France-Hawaii Telescope. They are respectively and . Such low values might be characteristic of a frosty and porous regolith fractured by cracks or of very porous particle aggregates. Particles have to be slowly spinning to explain the observed ring temperatures. A large azimuthal asymmetry with an amplitude about 1 K is detected on the West ansa of the B ring. It cannot be explained by a model that considers the ring as a slab of low thermal inertia rapidly warming up to the sunlight after its eclipse into the planetary shadow.
Key words: planetary rings -- infrared: solar system -- conduction -- radiation mechanism: thermal
© ESO 2005