Search Publications
Thermophysical property variations across Dione and Rhea
Spencer, J. R.; Howett, C. J. A.; Segura, M. +2 more
Maps of the variation in bolometric Bond albedo and thermal inertia across Rhea and Dione have been produced using various day and nighttime observations, taken by Cassini's Composite Infrared Spectrometer (CIRS). The albedo maps show the same trend that has been previously observed on these satellites from reflected sunlight and thermal observati…
Equilibrium composition between liquid and clathrate reservoirs on Titan
Sotin, Christophe; Mousis, Olivier; Choukroun, Mathieu +1 more
Hundreds of lakes and a few seas of liquid hydrocarbons have been observed by the Cassini spacecraft to cover the polar regions of Titan. A significant fraction of these lakes or seas could possibly be interconnected with subsurface liquid reservoirs of alkanes. In this paper, we investigate the interplay that would happen between a reservoir of l…
Numerical simulation of tides and oceanic angular momentum of Titan’s hydrocarbon seas
Lorenz, Ralph D.; Tokano, Tetsuya; Van Hoolst, Tim
Tides and tidal currents in Titan's hydrocarbon seas are numerically simulated by a 3-dimensional ocean circulation model using a bathymetry map constrained by Cassini. These predictions are used to calculate the tidally induced variations of the oceanic angular momentum of the seas. The tides behave as a quasi-standing wave with anti-nodes at the…
Wind circulation regimes at Venus' cloud tops: Ground-based Doppler velocimetry using CFHT/ESPaDOnS and comparison with simultaneous cloud tracking measurements using VEx/VIRTIS in February 2011
Widemann, Thomas; Machado, Pedro; Luz, David +1 more
We present new results based on ground-based Doppler spectroscopic measurements, obtained with the ESPaDOnS spectrograph at Canada-France-Hawaii telescope (CFHT) and simultaneous observations of velocity fields, obtained from space by the VIRTIS-M instrument on board the Venus Express spacecraft. These measurements are based on high-resolution spe…
Iapetus' near surface thermal emission modeled and constrained using Cassini RADAR Radiometer microwave observations
Lorenz, R. D.; Wye, L. C.; Janssen, M. A. +5 more
Since its arrival at Saturn, the Cassini spacecraft has had only a few opportunities to observe Iapetus, Saturn's most distant regular satellite. These observations were all made from long ranges (>100,000 km) except on September 10, 2007, during Cassini orbit 49, when the spacecraft encountered the two-toned moon during its closest flyby so fa…
From Voyager-IRIS to Cassini-CIRS: Interannual variability in Saturn’s stratosphere?
Fletcher, L. N.; Irwin, P. G. J.; Sinclair, J. A. +4 more
We present an intercomparison of Saturn’s stratosphere between Voyager 1-IRIS observations in 1980 and Cassini-CIRS observations in 2009 and 2010. Over a saturnian year (∼29.5 years) has now passed since the Voyager flybys of Saturn in 1980/1981. Cassini observations in 2009/2010 capture Saturn in the same season as Voyager observations (just afte…
Catastrophic ice lake collapse in Aram Chaos, Mars
Kleinhans, Maarten G.; Zegers, Tanja E.; Oosthoek, Jelmer H. P. +1 more
Hesperian chaotic terrains have been recognized as the source of outflow channels formed by catastrophic outflows. Four main scenarios have been proposed for the formation of chaotic terrains that involve different amounts of water and single or multiple outflow events. Here, we test these scenarios with morphological and structural analyses of im…
A comprehensive NMR structural study of Titan aerosol analogs: Implications for Titan's atmospheric chemistry
Smith, Mark A.; He, Chao
Titan has a thick atmosphere composed primarily of nitrogen and methane. Complex organic chemistry induced by solar ultraviolet radiation and energetic particles, takes place in Titan's upper atmosphere, producing an optically thick reddish brown carbon based haze encircling this moon. The chemistry in Titan's atmosphere and its resulting chemical…
Time variations of O2(a1Δ) nightglow spots on the Venus nightside and dynamics of the upper mesosphere
Drossart, Pierre; Piccioni, Giuseppe; Gérard, Jean-Claude +1 more
The dynamical regime of the Venus upper atmosphere is mainly decomposed into three regions. The first one, located below 65 km of altitude is governed by the retrograde superrotational zonal (RSZ) circulation. The second region above 130 km is dominated by the subsolar to antisolar (SS-AS) circulation. The dynamics of the transition region in betw…
Non-circular features in Saturn’s D ring: D68
Hedman, M. M.; Burns, J. A.; Showalter, M. R. +1 more
D68 is a narrow ringlet located only 67,627 km (1.12 planetary radii) from Saturn’s spin axis. Images of this ringlet obtained by the Cassini spacecraft reveal that this ringlet exhibits persistent longitudinal brightness variations and a substantial eccentricity (ae=25±1 km). By comparing observations made at different times, we confirm that the …