9 research outputs found

    Singular regional brightening events on Titan as seen by Cassini/VIMS

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    Titan, the largest satellite of Saturn, is the only satellite in the solar system with a dense atmosphere. The close and continuous observations of Titan by the Cassini spacecraft, in orbit around Saturn since July 2004, bring us evidences that Titan tropo-sphere and low stratosphere experience an exotic, but complete meteorological cycle similar to the Earth hy-drological cycle, with hydrocarbons evaporation, con-densation in clouds, and rainfall. Cassini monitoring campaigns also demonstrate that Titan’s cloud cover-age and climate vary with latitude. Titan’s tropics, with globally weak meteorological activity and widespread dune fields, seem to be slightly more arid than the poles, where extensive and numerous liquid reservoirs and sustained cloud activity were discovered. Only a few tropospheric clouds have been observed at Titan’s tropics during the southern summer [2-4]. As equinox was approaching (in August 2009), they oc-curred more frequently and appeared to grow in strength and size [5-7]

    Temperate Lakes on Titan

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    For my Ph.D. dissertation, I investigate the relationship between lakes and climate on Titan. I first view Titan's surface at the visible wavelengths of the VIMS-VIS instrument and find two new atmospheric windows at 653 and 681 nm. Following up on observations of clouds around the 40S latitude band, I surveyed the southern temperate latitudes finding two lake features. The total estimated volume of the larger of these lakes, Sionascaig Lacus, falls within the estimates of methane inventory in the clouds observed over this region. A survey of the northern mid-latitudes reveals three candidate features I reason to be lakes and would serve as interesting targets for future Cassini flybys. The existence of temperate lakes and lake candidates adds further constraints to Titan GCMs and adds to the complexity of Titan's polar lake asymmetry.Thesis (Ph.D., Physics) -- University of Idaho, 201

    Possible temperate lakes on Titan

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    International audienceWe analyze southern mid-latitude albedo-dark features on Titan observed by Cassini's Visual and Infrared Mapping Spectrometer (VIMS). In exploring the nature of these features we consider their morphology, albedo, and specular reflectivity. We suggest that they represent candidates for potential temperate lakes. The presence of lakes at the mid-latitudes would indicate that surface liquid can accumulate and remain stable away from Titan's poles. Candidate lakes were identified by looking for possible shorelines with lacustrine morphology. Then, we applied an atmospheric correction that empirically solved for their surface albedo. Finally, we looked for a specular reflection of the sky in the identified candidates. Using this prescription, we find two candidates that remain as potential temperature lakes. If candidate features do represent temperate lakes on Titan, they have implications for formation mechanisms such as clouds and rainfall or, in low elevation areas, percolation and subsurface flow. Clouds were observed near candidate lake locations on the T66 flyby and this latitude band showed many clouds during southern summer. Our techniques can be applied to areas of Titan that lack RADAR coverage to search for mid-and low-latitude lakes in the future

    Organic sedimentary deposits in Titan’s dry lakebeds: Probable evaporite

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    We report the discovery of organic sedimentary deposits at the bottom of dry lakebeds near Titan’s north pole in observations from the Cassini Visual and Infrared Mapping Spectrometer (VIMS). We show evidence that the deposits are evaporitic, making Titan just the third known planetary body with evaporitic processes after Earth and Mars, and is the first that uses a solvent other than water

    VIMS spectral mapping observations of Titan during the Cassini prime mission

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    This is a data paper designed to facilitate the use of and comparisons to Cassini/visual and infrared mapping spectrometer (VIMS) spectral mapping data of Saturn's moon Titan. We present thumbnail orthographic projections of flyby mosaics from each Titan encounter during the Cassini prime mission, 2004 July 1 through 2008 June 30. For each flyby we also describe the encounter geometry, and we discuss the studies that have previously been published using the VIMS dataset. The resulting compliation of metadata provides a complementary big-picture overview of the VIMS data in the public archive, and should be a useful reference for future Titan studies
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