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Titan's Tropical Storms in an Evolving Atmosphere

McKay, Christopher P.; Griffith, Caitlin A.; Ferri, Francesca

The Huygens probe landed in a damp lake bed fed by fluvial channels, indicative of past rainfall. Such washes, interspersed with vast dunes, are typical of Titan's tropical landscape. Yet, Cassini-Huygens measurements reveal a highly stable tropical atmosphere devoid of deep convective storms, and the formation of washes in dune fields is not unde…

Isotopic Ratios in Titan's Atmosphere from Cassini CIRS Limb Sounding: HC₃N in the North

Irwin, P. G. J.; Teanby, N. A.; Flasar, F. M. +8 more

This Letter reports the first detection of the three ¹³C isotopologues of HC₃N on Titan, from Cassini Composite Infrared Spectrometer (CIRS) infrared spectra. The data are limb spectra taken at latitudes N54°-N69° in 2006 and 2007 when HC₃N was enhanced in the north. Using a new line list for the ν₅ band…

Isotopic Ratios in Titan's Atmosphere from Cassini CIRS Limb Sounding: CO₂ at Low and Midlatitudes

Irwin, P. G. J.; Teanby, N. A.; Flasar, F. M. +8 more

This Letter reports on a search for infrared emissions of isotopologues of CO₂ in the atmosphere of Titan using spectral data recorded by the Cassini Composite Infrared Spectrometer (CIRS). We have made a successful 6.5 σ detection of ¹³CO₂ at a fraction CO₂/¹³CO₂ = 84 ± 17, consist…

Photochemical Enrichment of Deuterium in Titan's Atmosphere: New Insights from Cassini-Huygens

Mousis, Olivier; Lunine, Jonathan I.; Vuitton, Véronique +2 more

Cassini-Huygens data are used to reexamine the potential sources of the D/H enhancement over solar, measured in methane, in Titan's atmosphere. Assuming that the system is closed with respect to carbon, the use of constraints from the Huygens probe for the determination of the current mass of atmospheric methane and the most up-to-date determinati…

No Evidence of Morning or Large-Scale Drizzle on Titan

Geballe, Thomas R.; Kim, Sang J.; Trafton, Laurence M.

Widespread methane precipitation on Titan has been predicted by several authors since methane saturation in the upper troposphere was measured by the Huygens probe over its landing site. Recently, observational evidence of widespread morning drizzle has been suggested based on detection of a dark morning site in surface-subtracted 2 µm spect…

First High Solar Phase Angle Observations of Rhea Using Cassini VIMS: Upper Limits on Water Vapor and Geologic Activity

Brown, R. H.; Buratti, B. J.; Nicholson, P. D. +5 more

Using radiances acquired with Cassini's Visual and Infrared Mapping Spectrometer (VIMS), we construct high solar phase angle curves for Saturn's second largest moon, Rhea. Ground-based studies of Rhea and Saturnian icy satellites are focussing on low phase angles; to our knowledge, these are the first solar phase curve data for Rhea on phase angle…