Cassini thermal observations of Saturn's main rings: Implications for particle rotation and vertical mixing - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Planetary and Space Science Année : 2006

Cassini thermal observations of Saturn's main rings: Implications for particle rotation and vertical mixing

Linda Spilker
  • Fonction : Auteur
Stuart Pilorz
  • Fonction : Auteur
Brad Wallis
  • Fonction : Auteur
John Pearl
  • Fonction : Auteur
Jeffrey Cuzzi
  • Fonction : Auteur
Shawn Brooks
  • Fonction : Auteur
Nicolas Altobelli
  • Fonction : Auteur
Scott Edgington
  • Fonction : Auteur
Mark Showalter
  • Fonction : Auteur
F. Michael Flasar
  • Fonction : Auteur

Résumé

In late 2004 and 2005 the Cassini composite infrared spectrometer (CIRS) obtained spatially resolved thermal infrared radial scans of Saturn's main rings (A, B and C, and Cassini Division) that show ring temperatures decreasing with increasing solar phase angle, α, on both the lit and unlit faces of the ring plane. These temperature differences suggest that Saturn's main rings include a population of ring particles that spin slowly, with a spin period greater than 3.6 h, given their low thermal inertia. The A ring shows the smallest temperature variation with α, and this variation decreases with distance from the planet. This suggests an increasing number of smaller, and/or more rapidly rotating ring particles with more uniform temperatures, resulting perhaps from stirring by the density waves in the outer A ring and/or self-gravity wakes. The temperatures of the A and B rings are correlated with their optical depth, τ, when viewed from the lit face, and anti-correlated when viewed from the unlit face. On the unlit face of the B ring, not only do the lowest temperatures correlate with the largest τ, these temperatures are also the same at both low and high α, suggesting that little sunlight is penetrating these regions. The temperature differential from the lit to the unlit side of the rings is a strong, nearly linear, function of optical depth. This is consistent with the expectation that little sunlight penetrates to the dark side of the densest rings, but also suggests that little vertical mixing of ring particles is taking place in the A and B rings.
Fichier non déposé

Dates et versions

hal-03821747 , version 1 (19-10-2022)

Identifiants

Citer

Linda Spilker, Stuart Pilorz, Brad Wallis, John Pearl, Jeffrey Cuzzi, et al.. Cassini thermal observations of Saturn's main rings: Implications for particle rotation and vertical mixing. Planetary and Space Science, 2006, 54 (12), pp.1167-1176. ⟨10.1016/j.pss.2006.05.033⟩. ⟨hal-03821747⟩
8 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More