Titan's topography, strange.... |
Titan's topography, strange.... |
Apr 12 2009, 12:44 PM
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#1
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Recent article in Science by Zebker et al.:
Zebker et al. Science in press, "Size and Shape of Saturn's Moon Titan". doi: 10.1126/science.1168905 (published online April 2, 2009) Link to abstract (pay-for article): http://www.sciencemag.org/cgi/content/abstract/1168905 Article on spaceref discusses this paper: http://www.spaceref.com/news/viewpr.html?pid=27912 Figure 3 from the Science article is a global elevation map relative to barycenter. Key points of article:
"Xanadu seems to be systematically lower than other parts of the equatorial belt, and not uplifted like most mountainous areas on Earth." (quote from Fig. 3 caption in article) -Mike -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Apr 13 2009, 02:07 AM
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#2
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
The channel drainage pattern in W Xanadu in the T13 SAR RADAR Swath is very consistent with the Zebker elevation data.
(For E Xanadu, check out Fig 2b the freely available LPSC abstract: http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1037.pdf. For W Xanadu, check out Fig. 7 a and b in Lorenz et al. Planetary and Space Science 56 (2008) 1132-1144. "Fluvial Channels on Titan: Initial Cassini RADAR observations." doi: 10.1016/j.psss.2008.02.009 The dendritic drainage pattern across the T13 RADAR Swath pattern is to the S, towards the lowest regional barycentric elevation determined to be in SW Xanadu. Thus, the elevation data seems to agree with the local geoid in W Xanadu. Back to the tough question, what prevents the Shangri-La dune sands from dropping down into the SW Xanadu low elevation basin??? **** The Zebker paper also makes the airfall origin of the sand sea dunes difficult to explain. If atmospheric deposition and sintering is supposedly occuring all over, it should occur over Xanadu. The regional gradient should make it collect in the SW Xanadu basin. According to this idea, there should be a dune sea filling in the SW Xanadu depression. But there isn't. (At least no dunes are seen by RADAR, and ISS shows a bright coating rather than a dark dune sea.) There is, however, a smooth (RADAR) dark area seen with channels crossing into it, again going downgradient. -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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