Active Dune Gullies in Kaiser Crater
NASA/JPL/University of Arizona
Active Dune Gullies in Kaiser Crater
ESP_025900_1330  Science Theme: Aeolian Processes
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Gullies remain an interesting feature to study on Mars, especially because we are still learning about their formation and what processes still act on them.

In this observation, we see large gullies on a huge, barchan dune. We've observed these gullies before, seeing that they appear to be active at different times. When we say "active," we mean that we can see changes in their appearance between different HiRISE images of the same area.

The major objective of this and similar images is to better understand the mechanism for these changes. A specific hypothesis the HiRISE team is investigating is that the changes we see are associated with frost deposits. The frost may be thick and heavy enough to cause parts of the sand dune to collapse, especially if it is "lubricated" by a layer of gas at the base of the frost layer. The gas would form at the bottom of the frost if sunlight passes through the frost and heats the underlying dark sand, working like a greenhouse.

Written by: HiRISE Science Team   (18 April 2012)

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Acquisition date
04 February 2012

Local Mars time:
15:16

Latitude (centered)
-46.739°

Longitude (East)
20.145°

Range to target site
253.5 km (158.4 miles)

Original image scale range
25.4 cm/pixel (with 1 x 1 binning) so objects ~76 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle:
7.3°

Phase angle:
78.5°

Solar incidence angle
83°, with the Sun about 7° above the horizon

Solar longitude
66.1°, Northern Spring

North azimuth:
97°

Sub-solar azimuth:
51.4°
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NASA/JPL/University of Arizona



Postscript
For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.