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The Orbits of the Main Saturnian Satellites, the Saturnian System Gravity Field, and the Orientation of Saturn's Pole
Jacobson, Robert. A.
Four spacecraft have been sent to investigate the Saturnian system: Pioneer 11, Voyager 1, Voyager 2, and Cassini. By analyzing data acquired with these spacecraft together with Earth-based and Hubble Space Telescope satellite astrometry and Saturnian ring and satellite occultations, we constructed a model for the orientation and precession of Sat…
Ephemerides of the Irregular Saturnian Satellites from Earth-based Astrometry and Cassini Imaging
Jacobson, Robert A.; Sheppard, Scott S.; Brozović, Marina +2 more
We report a new determination of the orbits of the irregular Saturnian satellites. We fit their numerically integrated orbits to a data set containing Earth-based observations and imaging data from the Cassini spacecraft. We include the statistics of the observation residuals, the satellites' orbital elements, and projected accuracies of the satel…
Kronoseismology. IV. Six Previously Unidentified Waves in Saturn’s Middle C Ring
Nicholson, P. D.; Hedman, M. M.; French, R. G.
Recent studies of stellar occultations observed by the Visual and Infrared Mapping Spectrometer on board the Cassini spacecraft have demonstrated that multiple spiral wave structures in Saturn’s rings are probably generated by normal-mode oscillations inside the planet. Wavelet-based analyses have been able to unambiguously determine both the numb…
Observational Constraints on Planet Nine: Cassini Range Observations
Holman, Matthew J.; Payne, Matthew J.
We examine the tidal perturbations induced by a possible additional, distant planet in the solar system on the distance between the Earth and the Cassini spacecraft. We find that measured range residuals alone can significantly constrain the sky position, distance, and mass of the perturbing planet to sections of the sky essentially orthogonal to …
Enceladus’ Geysers: Relation to Geological Features
Porco, Carolyn C.; Helfenstein, Paul
We apply histogram analysis, photogeological methods, and tidal stress modeling to Porco et al.'s survey of 101 Enceladus South Polar Basin geysers and their three-dimensional orientations to test if the jet azimuths are influenced by their placement relative to surface morphology and tectonic structures. Geysers emplaced along the three most acti…
Saturn´s Inner Satellites: Orbits, Masses, and the Chaotic Motion of Atlas from New Cassini Imaging Observations
Cooper, N. J.; Murray, C. D.; Evans, M. W. +1 more
We present numerically derived orbits and mass estimates for the inner Saturnian satellites, Atlas, Prometheus, Pandora, Janus, and Epimetheus from a fit to 2580 new Cassini Imaging Science Subsystem astrometric observations spanning 2004 February to 2013 August. The observations are provided as machine-readable and Virtual Observatory tables. We …
Tracking the Geysers of Enceladus into Saturn’s E Ring
Porco, C. C.; Mitchell, C. J.; Weiss, J. W.
We examine Cassini Imaging Science Subsystem images of the E ring taken over a period of almost 7 yr, from 2006 September to 2013 July, in which long, sinuous structures dubbed tendrils are present. We model these structures by numerically integrating the trajectories of particles launched from the sources of the most active geysers recently locat…
How the Geysers, Tidal Stresses, and Thermal Emission across the South Polar Terrain of Enceladus are Related
Nimmo, Francis; Porco, Carolyn; DiNino, Daiana
We present the first comprehensive examination of the geysering, tidal stresses, and anomalous thermal emission across the south pole of Enceladus and discuss the implications for the moon's thermal history and interior structure. A 6.5 yr survey of the moon's south polar terrain (SPT) by the Cassini imaging experiment has located ~100 jets or gey…
Tidally Modulated Eruptions on Enceladus: Cassini ISS Observations and Models
Nimmo, Francis; Porco, Carolyn; Mitchell, Colin
We use images acquired by the Cassini Imaging Science Subsystem (ISS) to investigate the temporal variation of the brightness and height of the south polar plume of Enceladus. The plume's brightness peaks around the moon's apoapse, but with no systematic variation in scale height with either plume brightness or Enceladus' orbital position. We comp…
Exploring Overstabilities in Saturn's A Ring Using Two Stellar Occultations
Nicholson, P. D.; Hedman, M. M.; Salo, H.
Certain regions of Saturn's rings exhibit periodic opacity variations with characteristic radial wavelengths of up to a few hundred meters that have been attributed to viscous overstabilities. The Visual and Infrared Mapping Spectrometer on board the Cassini spacecraft observed two stellar occultations of the star γ Crucis that had sufficient reso…