Star Dunes in a Crater in Tyrrhena Terra
Star Dunes in a Crater in Tyrrhena Terra
ESP_017036_1665  Science Theme: Composition and Photometry
An amazing aspect of Mars that is captured in many HiRISE images is geologic diversity within a small area. This image, of a crater in the Tyrrhena Terra region, was targeted to look at the geologic aspects of possible clays detected with the CRISM instrument.

Fortuitously, a beautiful set of star dunes are visible on the western edge of a small crater within the larger target crater (this smaller crater is in the lower left of the image). Star dunes form when sand is blown by winds coming from multiple directions, which is common in craters. This results in intersecting dunes, forming a polygonal, or “star” pattern.

Here we show two zooms of the star dunes. The closest zoom (at right) shows lumpy deposits of sand in the interior of the star patterns, probably resulting from avalanches off of the dune slopes. The dune sands are most likely made of basalt, a common volcanic rock. The possible clay-bearing material is probably within the surrounding bedrock.

Written by: Nathan Bridges  (5 May 2010)
Acquisition date
15 March 2010

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
257.2 km (159.8 miles)

Original image scale range
from 25.8 cm/pixel (with 1 x 1 binning) to 51.6 cm/pixel (with 2 x 2 binning)

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
59°, with the Sun about 31° above the horizon

Solar longitude
64.5°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  43.3°
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IRB color
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Merged IRB
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Merged RGB
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RGB color
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Black and white
map-projected   (634MB)

IRB color
map-projected   (367MB)

Black and white
map-projected  (322MB)
non-map           (273MB)

IRB color
map projected  (135MB)
non-map           (356MB)

Merged IRB
map projected  (178MB)

Merged RGB
map-projected  (168MB)

RGB color
non map           (357MB)
10K (TIFF)

B&W label
Color label
Merged IRB label
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IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:

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. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.