Moonlet Wakes in Saturn's Cassini Division
L.J. Spilker (formerly Horn) (JPL/Caltech), M.R. Showalter (Stanford)
We have detected several features with wavelike characteristics in the Voyager Radio Science (RSS) earth occultation data and Voyager photopolarimeter (PPS) stellar occultation data of Saturn's Cassini Division. We identified these structures using a non-linear autoregressive power spectral algorithm called Burg. This method is powerful for detecting short sections of quasiperiodic structure. We successfully used this same technique to identify six previously unseen Pan wakes in the Voyager PPS and Voyager RSS occultation data (Horn, Showalter and Russell, 1996, /it Icarus /bf 124, 663).
Applying the Burg technique to the RSS data we find a number of wavelike structures in the Cassini Division. We see three distinct features that look like moonlet wakes. Two are Cassini Division features detected by Marouf and Tyler (1986, /it Nature /bf 323, 120) in the Voyager RSS data. Flynn and Cuzzi (1989, /it Icarus /bf 82, 180) determined that these features were azimuthally symmetric in the Voyager images and were most likely not moonlet wakes. The third wavelike structure resembles an outer moonlet wake. If it is a wake it may correspond to a previously undetected moonlet located in a Cassini Division gap between 118,929 km and 118,966 km.
We see at least one wavelike feature in the PPS data. This feature
falls close to the outer edge of the Huygens gap in the Cassini
Division. It is consistent with an outer moonlet wake. If it is a
wake it may correspond to a previously undetected moonlet inside the
Huygens gap. Several other wavelike features in the Cassini Division
resemble moonlet wakes. We plan to pursue these structures further in
the future. This work was performed at JPL/Caltech under contract with
NASA.