Search Publications
Observation of a tilt of Titan's middle-atmospheric superrotation
Nixon, Conor A.; Achterberg, Richard K.; Flasar, F. Michael +2 more
Maps of isotherms on surfaces of constant pressure in Titan's middle atmosphere encircle the poles but show an offset, implying that the mean zonal flow has an axis of symmetry that is tilted relative to the spin axis of the solid body. The effect is seen in both hemispheres around a consistent axis. Periodogram analysis of the temperature field s…
Jupiter's polar clouds and waves from Cassini and HST images: 1993 2006
Hueso, R.; Sánchez-Lavega, A.; Pérez-Hoyos, S. +1 more
For a variety of reasons, Jupiter's polar areas are probably the less observed regions of the planet. To study the dynamics and cloud vertical structure in the polar regions of the planet (latitudes 50° to 80° in both hemispheres) we have used images of Jupiter obtained from the ultraviolet to near infrared (258 to 939 nm) by the Cassini Imagining…
Observations of atmospheric water vapor above the Tharsis volcanoes on Mars with the OMEGA/MEx imaging spectrometer
Maltagliati, Luca; Bibring, Jean-Pierre; Langevin, Yves +6 more
The OMEGA imaging spectrometer onboard the Mars Express spacecraft is particularly well suited to study in detail specific regions of Mars, thanks to its high spatial resolution and its high signal-to-noise ratio. We investigate the behavior of atmospheric water vapor over the four big volcanoes located on the Tharsis plateau (Olympus, Ascraeus, P…
Can Cassini detect a subsurface ocean in Titan from gravity measurements?
Iess, Luciano; Tortora, Paolo; Lunine, Jonathan I. +6 more
Recent models of Titan's interior predict that the satellite contains an ocean of water and ammonia under an icy layer. Direct evidence for the presence of an ocean can be provided on the Cassini mission only by radio science determination of Titan Love number k. Simulations that use the five flybys T11, T22 T33, T45, and T68 (the latter two belon…
Astrometry and dynamics of Anthe (S/2007 S 4), a new satellite of Saturn
Porco, C. C.; Cooper, N. J.; Murray, C. D. +3 more
We describe the astrometry and dynamics of Anthe (S/2007 S 4), a new satellite of Saturn discovered in images obtained using the Imaging Science Subsystem (ISS) of the Cassini spacecraft. Included are details of 63 observations, of which 28 were obtained with Cassini's narrow-angle camera (NAC) and 35 using its wide-angle camera (WAC), covering an…
Dust aerosols above the south polar cap of Mars as seen by OMEGA
Bibring, J. -P.; Gondet, B.; Langevin, Y. +4 more
The time evolution of atmospheric dust at high southern latitudes on Mars has been determined using observations of the south seasonal cap acquired in the near infrared (1-2.65 µm) by OMEGA/Mars Express in 2005. Observations at different solar zenith angles and one EPF sequence demonstrate that the reflectance in the 2.64 µm saturated …
Condensation in Titan's stratosphere during polar winter
Irwin, P. G. J.; Teanby, N. A.; de Kok, R.
In Titan's north polar region stratospheric clouds are expected to form due to a combination of low temperatures and downward motion of volatile-enriched air. Here we investigate possible sources of stratospheric clouds at Titan's pole using data from the Cassini Composite Infrared Spectrometer and a simple condensation model. An upper limit for C…
Removal of Titan's noble gases by their trapping in its haze
Bar-Nun, Akiva; Jacovi, Ronen
Titan's haze, formed by photolysis of C 2H 2, C 2H 4 and HCN, was found experimentally to trap Ar, Kr and Xe with efficiencies of 3.5 × 10 -4, 1.9 × 10 -3 and 6.5 × 10 -2 [noble gas atom]/[carbon atom] in the polymer, respectively. The rate of aerosol formation and settli…
Titan's surface from reconciled Cassini microwave reflectivity and emissivity observations
Janssen, Michael A.; Cassini Radar Team; Wye, Lauren C. +1 more
The surface of Titan, Saturn's largest moon, appears to consist of solid hydrocarbons or CO 2 with considerable small-scale structure, according to a new electromagnetic scattering model that uses both Cassini radar reflectivity and emissivity measurements. Our model resolves a well-known ambiguity in active and passive observations of …
Recent volcano ice interaction and outburst flooding in a Mars polar cap re-entrant
Hovius, Niels; Lea-Cox, Andrew; Turowski, Jens M.
Formation of chasms in the polar ice caps of Mars has been attributed to meltwater outburst floods, but the cause of melting has remained uncertain. In a cap re-entrant enveloping Abalos Colles, west of Casma Boreale in the north polar cap, we have found possible evidence of recent volcano-ice interaction and outburst flooding. In this paper we de…