Search Publications
The Nitrogen Chemistry of Titan's Upper Atmosphere Revealed
Yelle, R. V.; Vuitton, V.; Anicich, V. G.
Titan's atmosphere is unique because dissociation of N2 and CH4, the primary atmospheric constituents, provides the H, C, and N atoms necessary for the synthesis of complex organic molecules. The first steps in the synthesis of organic molecules occur in the upper atmosphere where energetic photons and electrons dissociate N<…
Spitzer MIPS Infrared Imaging of M31: Further Evidence for a Spiral-Ring Composite Structure
Barmby, P.; Krause, O.; Gordon, K. D. +16 more
New images of M31 at 24, 70, and 160 µm taken with the Multiband Imaging Photometer for Spitzer (MIPS) reveal the morphology of the dust in this galaxy. This morphology is well represented by a composite of two logarithmic spiral arms and a circular ring (radius ~10 kpc) of star formation offset from the nucleus. The two spiral arms appear t…
The Enceladus and OH Tori at Saturn
Tokar, R. L.; Johnson, R. E.; Sittler, E. C. +4 more
The remarkable observation that Enceladus, a small icy satellite of Saturn, is actively venting has led to the suggestion that ejected water molecules are the source of the toroidal atmosphere observed at Saturn for over a decade using the Hubble Space Telescope (HST). Here we show that the venting leads directly to a new feature, a narrow Encelad…
Enceladus: A Source of Nitrogen and an Explanation for the Water Vapor Plume Observed by Cassini
Loeffler, M. J.; Raut, U.; Baragiola, R. A.
Recently, the Cassini spacecraft observed an unexpected emission of plumes of water vapor, nitrogen, and icy particles from the southern polar region of Saturn's icy moon Enceladus. While these findings support previous ideas of geological activity in this icy moon, there is no experimental evidence explaining how these plumes could be produced at…
Unravelling Temporal Variability in Saturn's Spiral Density Waves: Results and Predictions
Nicholson, Philip D.; Porco, Carolyn C.; Hedman, Matthew M. +2 more
We describe a model that accounts for the complex morphology of spiral density waves raised in Saturn's rings by the co-orbital satellites, Janus and Epimetheus. Our model may be corroborated by future Cassini observations of these time-variable wave patterns.