Search Publications
Saturn's Planetary Period Oscillations During the Closest Approach of Cassini's Ring-Grazing Orbits
Dougherty, M. K.; Cowley, S. W. H.; Provan, G. +2 more
Saturn's planetary period oscillations (PPOs) are ubiquitous throughout its magnetosphere. We investigate the PPO's azimuthal magnetic field amplitude interior to the field-aligned currents, during the closest approaches of Cassini's ring-grazing orbits (October 2016 to April 2017), with periapses at 2.5 RS. The amplitudes of the northe…
Cassini CAPS Identification of Pickup Ion Compositions at Rhea
Coates, A. J.; Thomsen, M. F.; Jones, G. H. +9 more
Saturn's largest icy moon, Rhea, hosts a tenuous surface-sputtered exosphere composed primarily of molecular oxygen and carbon dioxide. In this Letter, we examine Cassini Plasma Spectrometer velocity space distributions near Rhea and confirm that Cassini detected nongyrotropic fluxes of outflowing CO2+ during both the R1 and R1.5 encounters. Accou…
Photometric Modeling and VIS-IR Albedo Maps of Tethys From Cassini-VIMS
Clark, R. N.; Stephan, K.; D'Aversa, E. +6 more
We report about the derivation of visible (VIS) and infrared (IR) albedo maps and spectral indicators of Saturn's satellite Tethys from the complete Cassini-Visual and Infrared Mapping Spectrometer (VIMS) data set. The application of a photometric correction is necessary to remove illumination and viewing effects from the I/F spectra, to compute s…
First Observation of Lion Roar Emission in Saturn's Magnetosheath
Gurnett, D. A.; Hospodarsky, G. B.; Kurth, W. S. +3 more
We present an observation of intense emissions in Saturn's magnetosheath as detected by the Cassini spacecraft. The emissions are observed in the dawn sector (magnetic local time ∼06:45) of the magnetosheath over a time period of 11 h before the spacecraft crossed the bow shock and entered the unshocked solar wind. They are found to be narrow-band…
The Eye of Saturn's North Polar Vortex: Unexpected Cloud Structures Observed at High Spatial Resolution by Cassini/VIMS
Sotin, C.; Brown, R. H.; Baines, K. H. +6 more
Near-infrared spectral maps of Saturn's north polar vortex obtained at high spatial resolution provided by Cassini/Visual Infrared Mapping Spectrometer (VIMS) reveal localized ammonia clouds composed of unusually large particles exceeding 13 µm in radius, the largest cloud particles documented during the Cassini mission. Taken under near-opt…
The Search for Activity on Dione and Tethys With Cassini VIMS and UVIS
Brown, R. H.; Baines, K. H.; Buratti, B. J. +6 more
During the Cassini mission the Saturnian moons Dione and Tethys showed intriguing and multiple clues suggesting residual geologic activity that might be detectable as an atmosphere, plume, or even heat signature. These clues included an atmospheric aura around Dione, injection of particles into Saturn's magnetosphere, mysterious red streaks on Tet…
First Observation of Transport of Solar Wind Protons Scattered From Magnetic Anomalies Into the Near Lunar Wake: Observations by SARA/Chandrayaan-1
Barabash, Stas; Holmström, Mats; Futaana, Yoshifumi +5 more
We report the first observational evidence for the transport of the solar wind protons scattered from the lunar magnetic anomaly (LMA) into the near wake region from SWIM/Sub-keV Atom Reflecting Analyzer (SARA) aboard Chandrayaan-1. These protons with high angular spread are observed in the near wake region for specific orientations of interplanet…
Limits on Dione's Activity Using Cassini/CIRS Data
Spencer, John R.; Howett, Carly J. A.; Hurford, Terry +2 more
We use nighttime Cassini Composite Infrared Spectrometer (CIRS) data to look for discrete regions of elevated nighttime temperatures indicative of endogenic activity on Dione's surface. This is achieved by producing low latitude and midlatitude (less than 60°) maps of Dione's nighttime surface temperature, derived from 10 to 1,100-cm-1 …
Mysterious Linear Features Across Saturn's Moon Dione
Patthoff, D. Alex; Martin, Emily S.
Our mapping of the wispy terrains on Saturn's moons Dione has revealed unique linear features that are generally long (tens to hundreds of kilometers), narrow (<5 km), and brighter than the surrounding terrains. We refer to these features as linear virgae. Similar features, with a limited distribution, have been observed on Rhea. Wherever linea…
Titan's Variable Ionosphere During the T118 and T119 Cassini Flybys
Wahlund, J. -E.; Edberg, N. J. T.; Andrews, D. J. +6 more
We report on unusual dynamics in Titan's ionosphere as a significant difference in ionospheric electron density is observed between the T118 and T119 Cassini nightside flybys. Two distinct nightside electron density peaks were present during T118, at 1,150 and 1,200 km, and the lowest density ever observed in Titan's ionosphere at altitudes 1,000-…