The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show 100-meter ridges consistent with duneforms and reveal flow interactions with underlying hills. The distribution and orientation of the dunes support a model of fluctuating surface winds of 0.5 meter per second resulting from the combination of an eastward flow with a variable tidal wind. The existence of dunes also requires geological processes that create sand-sized (100- to 300-micrometer) particulates and a lack of persistent equatorial surface liquids to act as sand traps.
The sand seas of Titan: Cassini RADAR observations of longitudinal dunes / R. D., Lorenz; S., Wall; J., Radebaugh; G., Boubin; E., Reffet; M., Janssen; E., Stofan; R., Lopes; R., Kirk; C., Elachi; J., Lunine; K., Mitchell; F., Paganelli; L., Soderblom; C., Wood; L., Wye; H., Zebker; Y., Anderson; S., Ostro; M., Allison; R., Boehmer; P., Callahan; P., Encrenaz; G. G., Ori; Franceschetti, Giorgio; Y., Gim; G., Hamilton; S., Hensley; W., Johnson; K., Kelleher; D., Muhleman; G., Picardi; F., Posa; L., Roth; R., Seu; S., Shaffer; B., Stiles; Vetrella, Sergio; E., Flamini; R., West. - In: SCIENCE. - ISSN 0036-8075. - STAMPA. - 312:5774(2006), pp. 724-727. [10.1126/science.1123257]
The sand seas of Titan: Cassini RADAR observations of longitudinal dunes
FRANCESCHETTI, GIORGIO;VETRELLA, SERGIO;
2006
Abstract
The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show 100-meter ridges consistent with duneforms and reveal flow interactions with underlying hills. The distribution and orientation of the dunes support a model of fluctuating surface winds of 0.5 meter per second resulting from the combination of an eastward flow with a variable tidal wind. The existence of dunes also requires geological processes that create sand-sized (100- to 300-micrometer) particulates and a lack of persistent equatorial surface liquids to act as sand traps.| File | Dimensione | Formato | |
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