Search Publications
Finding the trigger to Iapetus' odd global albedo pattern: Dynamics of dust from Saturn's irregular satellites
Hamilton, Douglas P.; Hedman, Matthew M.; Burns, Joseph A. +1 more
The leading face of Saturn's moon Iapetus, Cassini Regio, has an albedo only one tenth that on its trailing side. The origin of this enigmatic dichotomy has been debated for over 40 years, but with new data, a clearer picture is emerging. Motivated by Cassini radar and imaging observations, we investigate Soter's model of dark exogenous dust strik…
Ion flow and momentum transfer in the Venus plasma environment
Fedorov, A.; Barabash, S.; Lundin, R. +3 more
An analysis of ion data from 390 Venus Express, VEX, orbits demonstrates that the flow of solar wind- and ionospheric ions near Venus is characterized by a marked asymmetry. The flow asymmetry of solar wind H + and ionospheric O + points steadily in the opposite direction to the planet's orbital motion, and is most pronounced…
Waves in Cassini UVIS stellar occultations. 2. The C ring
Lissauer, Jack J.; Colwell, Joshua E.; Esposito, Larry W. +2 more
We performed a complete wavelet analysis of Saturn's C ring on 62 stellar occultation profiles. These profiles were obtained by Cassini's Ultraviolet Imaging Spectrograph High Speed Photometer. We used a WWZ wavelet power transform to analyze them. With a co-adding process, we found evidence of 40 wavelike structures, 18 of which are reported here…
Evidence for Amazonian northern mid-latitude regional glacial landsystems on Mars: Glacial flow models using GCM-driven climate results and comparisons to geological observations
Head, James W.; Forget, Francois; Fastook, James L. +2 more
A fretted valley system on Mars located at the northern mid-latitude dichotomy boundary contains lineated valley fill (LVF) with extensive flow-like features interpreted to be glacial in origin. We have modeled this deposit using glacial flow models linked to atmospheric general circulation models (GCM) for conditions consistent with the depositio…
The structure of Titan's atmosphere from Cassini radio occultations
French, Richard G.; Flasar, F. Michael; Marouf, Essam A. +7 more
We present results from the two radio occultations of the Cassini spacecraft by Titan in 2006, which probed mid-southern latitudes. Three of the ingress and egress soundings occurred within a narrow latitude range, 31-34°S near the surface, and the fourth at 52.8°S. Temperature-altitude profiles for all four occultation soundings are presented, an…
Monte Carlo modeling of neutral gas and dust in the coma of Comet 1P/Halley
Hansen, Kenneth C.; Gombosi, Tamas I.; Combi, Michael R. +4 more
The neutral gas environment of a comet is largely influenced by dissociation of parent molecules created at the surface of the comet and collisions of all the involved species. We compare the results from a kinetic model of the neutral cometary environment with measurements from the Neutral Mass Spectrometer and the Dust Impact Detection System on…
Power spectral analysis of Jupiter’s clouds and kinetic energy from Cassini
Showman, Adam P.; Choi, David S.
We present suggestive evidence for an inverse energy cascade within Jupiter’s atmosphere through a calculation of the power spectrum of its kinetic energy and its cloud patterns. Using Cassini observations, we composed full-longitudinal mosaics of Jupiter’s atmosphere at several wavelengths. We also utilized image pairs derived from these observat…
Sporadic formation of slope streaks on Mars
Schorghofer, Norbert; King, Christina M.
Slope streaks are a form of gravity-driven mass-movements that frequently occur on Mars today. The cause of slope streak formation remains unclear; both, dry and wet processes have been suggested. Here, we observationally constrain the time of the year during which slope streaks form. Imagery from four Mars-orbiting cameras is mined to identify lo…
The martian mesosphere as revealed by CO 2 cloud observations and General Circulation Modeling
González-Galindo, Francisco; Määttänen, Anni; Forget, François +1 more
Different missions have observed mesospheric clouds on Mars in the last years. The presence of these clouds implies, among other conditions, mesospheric temperatures below CO 2 condensation temperature. We use a General Circulation Model to study the mesospheric temperatures and compare the observed distribution of the mesospheric cloud…
Distribution of HCN in Titan's upper atmosphere from Cassini/VIMS observations at 3 µm
López-Puertas, M.; D'Aversa, E.; García-Comas, M. +5 more
Cassini/VIMS limb observations have been used to retrieve vertical profiles of hydrogen cyanide (HCN) from its 3 µm emission in the region from 600 to 1100 km altitude at daytime. While the daytime emission is large up to about 1100 km, it vanishes at nighttime at very low altitudes, suggesting that the daytime emission originates under non-…