Search Publications
Detection of phosphates originating from Enceladus's ocean
Postberg, Frank; Sekine, Yasuhito; Glein, Christopher R. +13 more
Saturn's moon Enceladus harbours a global1 ice-covered water ocean2,3. The Cassini spacecraft investigated the composition of the ocean by analysis of material ejected into space by the moon's cryovolcanic plume4-9. The analysis of salt-rich ice grains by Cassini's Cosmic Dust Analyzer10 enabled inferenc…
Saturn's atmospheric response to the large influx of ring material inferred from Cassini INMS measurements
Fletcher, Leigh N.; Guerlet, Sandrine; Moses, Julianne I. +12 more
During the Grand Finale stage of the Cassini mission, organic-rich ring material was discovered to be flowing into Saturn's equatorial upper atmosphere at a surprisingly large rate. Through a series of photochemical models, we have examined the consequences of this ring material on the chemistry of Saturn's neutral and ionized atmosphere. We find …
Saturn's Seismic Rotation Revisited
Fuller, Jim; Dewberry, Janosz W.; Mankovich, Christopher R.
Normal mode seismology is a promising means of measuring rotation in gas giant interiors, and ring seismology presents a singular opportunity to do so at Saturn. We calculate Saturn's normal modes of oscillation and zonal gravity field, using nonperturbative methods for normal modes in the rigidly rotating approximation, and perturbative methods f…
Excitation of Saturnian ECH Waves Within Remote Plasma Injections: Cassini Observations
Ni, Binbin; Gu, Xudong; Cao, Xing +7 more
Based on Cassini observations, we report representative electrostatic electron cyclotron harmonic (ECH) wave events observed in Saturn's magnetosphere within remote plasma injections. Unlike local injections, remote injections are "older" injection events that have evolved to form a dispersed signature in particle energy spectrum. We show that Sat…
Cassini Radio Occultation Observations of Saturn's Ionosphere: Electron Density Profiles From 2005 to 2013
Withers, Paul; Dalba, P. A.; Moore, L. +2 more
A set of electron density profiles of Saturn's ionosphere acquired by Cassini radio occultations is archived at the NASA Planetary Data System. However, the reference surface that defines zero altitude in these profiles is unknown and appears to vary by 1,500 km at fixed latitude. These profiles are immensely valuable for addressing questions pert…
Microwaving Mimas, Enceladus, Tethys, Dione, Rhea, Iapetus and Phoebe: Insights into the regolith properties and geological history of Saturn's icy satellites
Lellouch, Emmanuel; Wall, Stephen; Le Gall, Alice A. +4 more
While Saturn's main airless moons are all composed largely of water ice, their respective thermal histories and near environments have led to different regolith compositions and structures. Part of this history is recorded in their subsurface which can be probed by microwaves. Using a combined thermal and radiative transfer model, we here investig…
The Enigmatic Abundance of Atomic Hydrogen in Saturn's Upper Atmosphere
West, Robert A.; Ballester, Gilda E.; Moses, Julianne I. +5 more
A planet's Lyα emission is sensitive to its thermospheric structure. Here we report joint Hubble Space Telescope and Cassini cross-calibration observations of the Saturn Lyα emission made 2 weeks before the Cassini grand finale. To investigate the long-term Saturn Lyα airglow observed by different ultraviolet instruments, we cross-correlate their …
Temporal Evolution of Titan's Stratospheric Temperatures and Trace Gases from a Two-dimensional Retrieval of Cassini Composite Infrared Spectrometer Data
Achterberg, Richard K.
We use a two-dimensional (2D) radiative transfer model of Titan, which allows the atmospheric structure to vary in both altitude and latitude, to retrieve the spatial distribution of temperature, haze extinction, and C2H2, C2H6, C3H8, CH3C2H, C4H
The Bolometric Bond Albedo of Enceladus
West, Robert A.; Nixon, Conor A.; Fry, Patrick M. +13 more
The bolometric Bond albedo is a fundamental parameter of planets and moons. Here, combined observations from the Cassini spacecraft and the Hubble Space Telescope are used to determine the bolometric Bond albedo of Enceladus. We provide the full-disk reflectance of Enceladus across all phase angles (0° -180°) from 150 nm to 5131 nm, a spectral ran…
Phase locking among Saturn radio emissions revealed by Cassini observations
Xu, Yan; Fischer, Georg; Yao, Zhonghua +7 more
Context. Rotational modulation has been observed in different magnetospheric phenomena at Saturn, including radio emissions, which reflect the fundamental plasma processes in key regions. Though previous studies have shown Saturn's kilometric radiation, 5 kHz narrowband emissions, and auroral hiss to be rotationally modulated, the modulation featu…