Search Publications
O2(a1Δg) dayglow limb observations on Mars by SPICAM IR on Mars-Express and connection to water vapor distribution
Montmessin, F.; Bertaux, J. -L.; Fedorova, A. A. +3 more
The 1.27-µm O2(a1Δg) dayglow on Mars is a product of the ozone photolysis by solar UV radiation. The intensity of the O2(a1Δg) emission rate depends on ozone concentration, atmospheric density and kinetic parameters of involved photochemical reactions. In turn, the distributio…
Gravity waves in Titan's lower stratosphere from Huygens probe in situ temperature measurements
Young, Leslie A.; Lorenz, Ralph D.; Ferri, Francesca
The Huygens probe recorded atmospheric temperatures during its parachute descent through the atmosphere of Titan. A careful analysis of these data reveals for the first time spectacular but hitherto-unreported small-scale variations in stratospheric temperatures that we interpret as gravity waves, consistent with detection of such waves at higher …
The global precipitation of magnetospheric electrons into Titan's upper atmosphere
Yelle, R. V.; Snowden, D.
We couple a two-stream electron transport model to a three-dimensional model of Titan's plasma interaction to calculate the global precipitation of magnetospheric electrons into Titan's atmosphere. We describe energy deposition rates from eleven simulations that vary the following parameters: relative orientation of the solar and magnetospheric ra…
The discovery and dynamical evolution of an object at the outer edge of Saturn’s A ring
Murray, Carl D.; Cooper, Nicholas J.; Williams, Gareth A. +2 more
We report on the serendipitous discovery of an unresolved, evolving, sub-km-radius object with a semimajor axis <10 km inside that of the edge of Saturn’s main rings. The object has been detectable in Cassini images since at least May 2012 and its changing orbit shows evidence of a possible disruption in early 2013.
A survey of low-velocity collisional features in Saturn's F ring
Murray, Carl D.; Cooper, Nicholas J.; Williams, Gareth A. +1 more
Small (∼50 km scale), irregular features seen in Cassini images to be emanating from Saturn's F ring have been termed mini-jets by Attree et al. (2012). One particular mini-jet was tracked over half an orbital period, revealing its evolution with time and suggesting a collision with a local moonlet as its origin. In addition to these data we prese…
Landscape formation at the Deuteronilus contact in southern Isidis Planitia, Mars: Implications for an Isidis Sea?
Hiesinger, H.; Hauber, E.; Bernhardt, H. +3 more
Two of the most widely studied landforms that are associated with a putative ocean that filled the northern hemisphere of Mars are (1) the Vastitas Borealis Formation (VBF), plain units that cover a larger portion of the northern lowlands of Mars, and (2) a candidate paleoshoreline, e.g., the Deuteronilus contact, which represents the outer margin…
Modeling microwave backscatter and thermal emission from linear dune fields: Application to Titan
Lorenz, R. D.; Janssen, M. A.; Kirk, R. L. +1 more
We present an electromagnetic model that relates the microwave backscatter and thermal emission from linear dune fields to their compositional, physical (roughness, subsurface porosity/heterogeneity) and geometrical (slope, orientation) properties. This model shows the value of exploring these highly directional and geometrical features in light o…
An estimate of the dust pickup current at Enceladus
Gurnett, D. A.; Kurth, W. S.; Wahlund, J. -E. +3 more
We demonstrate that the acceleration of submicron dust originating at Enceladus by a reduced co-rotating E-field is capable of creating a dust pickup current perpendicular to the magnetic field with values ranging from 3 to 15 kA (depending upon the effective grain charge). Such a current represents a new contribution to the total pickup current i…
Quantitative analysis of the morphology of martian gullies and insights into their formation
Yue, Z.; Hu, W.; Liu, B. +4 more
The process of formation of observed geologically recent gully features on Mars has remained a topic of intense debate since their discovery. In this study, we performed quantitative morphological analysis on certain parameters of gullies from different settings, such as crater walls, terraces, and sand dunes, on the martian surface in addition to…
First observations of the Phoebe ring in optical light
Hedman, Matthew M.; Burns, Joseph A.; Tamayo, Daniel
The Phoebe ring, Saturn’s largest and faintest ring, lies far beyond the planet’s well-known main rings. It is primarily sourced by collisions with Saturn’s largest irregular satellite Phoebe, perhaps through stochastic macroscopic collisions, or through more steady micrometeoroid bombardment. The ring was discovered with the Spitzer Space Telesco…