Search Publications
Physical Properties and Galactic Distribution of Molecular Clouds Identified in the Galactic Ring Survey
Jackson, James M.; Roman-Duval, Julia; Heyer, Mark +2 more
We derive the physical properties of 580 molecular clouds based on their 12CO and 13CO line emission detected in the University of Massachusetts-Stony Brook (UMSB) and Galactic Ring surveys. We provide a range of values of the physical properties of molecular clouds, and find a power-law correlation between their radii and ma…
Physical Characteristics and Non-Keplerian Orbital Motion of "Propeller" Moons Embedded in Saturn's Rings
Porco, Carolyn C.; Hedman, Matthew M.; Burns, Joseph A. +8 more
We report the discovery of several large "propeller" moons in the outer part of Saturn's A ring, objects large enough to be followed over the 5 year duration of the Cassini mission. These are the first objects ever discovered that can be tracked as individual moons, but do not orbit in empty space. We infer sizes up to 1-2 km for the unseen moonle…
Cosmic-ray-mediated Formation of Benzene on the Surface of Saturn's Moon Titan
Liang, Mao-Chang; Yung, Yuk L.; Kaiser, Ralf I. +4 more
The aromatic benzene molecule (C6H6)—a central building block of polycyclic aromatic hydrocarbon molecules—is of crucial importance for the understanding of the organic chemistry of Saturn's largest moon, Titan. Here, we show via laboratory experiments and electronic structure calculations that the benzene molecule can be for…
Direct Evidence for Gravitational Instability and Moonlet Formation in Saturn's Rings
Cooper, N. J.; Murray, C. D.; Evans, M. W. +3 more
New images from the Cassini spacecraft reveal optically thick clumps, capable of casting shadows, and associated structures in regions of Saturn's F ring that have recently experienced close passage by the adjacent moon Prometheus. Using these images and modeling, we show that Prometheus' perturbations create regions of enhanced density and low re…
Seasonal Changes in Titan's Polar Trace Gas Abundance Observed by Cassini
Irwin, P. G. J.; Teanby, N. A.; de Kok, R. +1 more
We use a six-year data set (2004-2010) of mid-infrared spectra measured by Cassini's Composite InfraRed Spectrometer to search for seasonal variations in Titan's atmospheric temperature and composition. During most of Cassini's mission Titan's northern hemisphere has been in winter, with an intense stratospheric polar vortex highly enriched in tra…
D/H ratio of Titan from Observations of the Cassini/Composite Infrared Spectrometer
Flasar, F. M.; Achterberg, R. K.; Jennings, D. E. +9 more
The Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft, launched in 1997 October and inserted into Saturn's orbit in 2004 July for exploration of the Saturnian system, has been making observations of Titan during its close flybys. The infrared spectra of Titan observed over a wide range of latitudes cover the 10-1400 cm-1
Location and Magnetospheric Mapping of Saturn's Mid-latitude Infrared Auroral Oval
Cowley, Stanley W. H.; Melin, Henrik; Miller, Steve +2 more
Previous observations of Saturn's infrared aurorae have shown that a mid-latitude aurora exists significantly equatorward of the main auroral oval. Here, we present new results using data from four separate observing runs in 1998, 2003, 2008, and 2010. When combined, these provide a view of the mid-latitude aurora under a considerable range of vie…
Methane Gas Stabilizes Supercooled Ethane Droplets in Titan's Clouds
Wang, Chia C.; Signorell, Ruth; Kathrin Lang, E.
Strong evidence for ethane clouds in various regions of Titan's atmosphere has recently been found. Ethane is usually assumed to exist as ice particles in these clouds, although the possible role of liquid and supercooled liquid ethane droplets has been recognized. Here, we report on infrared spectroscopic measurements of ethane aerosols performed…
Impact of Coherent Backscattering on the Spectra of Icy Satellites of Saturn and the Implications of Its Effects for Remote Sensing
Buratti, B.; Kolokolova, L.; Tishkovets, V.
We have found systematic variations in the spectra of Saturn's icy satellites Rhea and Iapetus obtained by the Cassini Visual and Infrared Mapping Spectrometer (VIMS). The main attribute of these variations is a significantly different depth of the absorption bands at different phase angles. We show that these variations likely result from the coh…