Search Publications

Constraining Saturn's Interior with Ring Seismology: Effects of Differential Rotation and Stable Stratification

Fuller, Jim; Lai, Dong; Dewberry, Janosz W. +2 more

Normal mode oscillations in Saturn excite density and bending waves in the C ring, providing a valuable window into the planet's interior. Saturn's fundamental modes (f-modes) excite the majority of the observed waves, while gravito-inertial modes (rotationally modified g-modes) associated with stable stratification in the deep interior provide a …

Sampling Plume Deposits on Enceladus' Surface to Explore Ocean Materials and Search for Traces of Life or Biosignatures

Malaska, Michael J.; Choukroun, Mathieu; Backes, Paul +14 more

Enceladus is unique as an astrobiology target in that it hosts an active plume sourced directly from its habitable subsurface ocean. Ice particles from the plume contain geochemical constituents that are diagnostic of the ocean conditions, and may hold traces of life and/or biosignatures, if they exist. Up to 93% of the plume particles fall back o…

Titan in Transit: Ultraviolet Stellar Occultation Observations Reveal a Complex Atmospheric Structure

Tribbett, Patrick D.; Robinson, Tyler D.; Koskinen, Tommi T.

Transit spectroscopy is a key tool for exoplanet atmospheric characterization. However, transit spectrum observations can be limited by aerosol extinction when gas opacities are weak. The ultraviolet wavelength range contains a variety of strong molecular and atomic features, potentially enabling gas species detection even when atmospheric hazes a…

Heavy Positive Ion Groups in Titan's Ionosphere from Cassini Plasma Spectrometer IBS Observations

Coates, Andrew J.; Lavvas, Panayotis; Waite, J. Hunter +4 more

Titan's ionosphere contains a plethora of hydrocarbons and nitrile cations and anions as measured by the Ion Neutral Mass Spectrometer and Cassini Plasma Spectrometer (CAPS) on board the Cassini spacecraft. Data from the CAPS Ion Beam Spectrometer (IBS) sensor have been examined for five close encounters of Titan during 2009. The high relative vel…

Constraining the Positive Ion Composition in Saturn's Lower Ionosphere with the Effective Recombination Coefficient

Vigren, Erik; Wahlund, Jan-Erik; Dreyer, Joshua +4 more

The present study combines Radio and Plasma Wave Science/Langmuir Probe and Ion and Neutral Mass Spectrometer data from Cassini's last four orbits into Saturn's lower ionosphere to constrain the effective recombination coefficient α₃₀₀ from measured number densities and electron temperatures at a reference electron temperature of 300 K.…

No Evidence for Time Variation in Saturn's Internal Magnetic Field

Cao, Hao; Bloxham, Jeremy; Moore, Kimberly M. +2 more

The time variation of a planetary magnetic field can reveal important aspects of a planet's interior structure. Searching for time variation in planetary magnetic fields other than Earth has proved challenging owing to the small number of spacecraft missions flown to date, but such a detection may be possible given a sufficiently long baseline for…

Erratum: "Changes in a Dusty Ringlet in the Cassini Division after 2010" (2020, PSJ, 1, 43)

Bridges, Bill; Hedman, Matthew

Titan's "Average" Ionospheric Structures from Cassini

Ip, Wing-Huen; Hsu, Jen-Kai

The decadal observations of Titan's neutral atmosphere and ionosphere by the Ion and Neutral Mass Spectrometer mass spectrometer and other instruments on board the Cassini spacecraft at the Saturnian system provide a precious data set concerning the large-scale structure of Titan's upper ionosphere. An attempt is made in this study to generate ave…