Evidence of differential rotation inside Saturn from waves of its rings
Abstract
Saturn's average interior rotation rate has been estimated based on various analyses of its shape (Anderson and Schubert, 2007; Read et al., 2009; Helled et al., 2015), but we still have no clear information on its exact value and the degree of differential rotation versus depth.However, Hedman et al., (2009), Hedman and Nicholson (2014) and El Moutamid et al., (2016) have identified several structures in the main rings of Saturn which appear to be related to the planet's rotation rate.These structures (waves and perturbed edges) appear to be generated by so-called Tesseral Resonances, which are associated with gravity anomalies that rotate with Saturn's interior, rather than being driven by a satellite. Their locations are given by the usual formula for inner or outer Lindblad resonances.We have searched for additional wave-like signatures in stellar occultation data for the main rings which are related to the rotation period of Saturn and have identified several signatures consistent with other differential rotation in Saturn's interior. Our study of the behavior of the A, B and C rings uses images and occultation data obtained by the Cassini spacecraft over a period of 10 years from 2006 to 2015.
- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #48
- Pub Date:
- October 2016
- Bibcode:
- 2016DPS....4811403E