Bright and Dark Dunes
NASA/JPL/UArizona
Bright and Dark Dunes
ESP_067775_1120  Science Theme: Aeolian Processes
This image shows a large sand dune with bright patches. Martian dunes near the poles often have bright patches in the spring, when seasonal frost is lingering. However, this image is from late summer, when frost is long gone. What is going on here?

A close-up look with HiRISE provides some clues. The bright patches are made up of large ridges that look like wind-blown bedforms. Additionally, the bright patches are yellowish in the infrared-red-blue image. In enhanced color, most sand on Mars is blue but dust is yellow. This suggests that the bright bedforms are either built from, or covered by, dust or material with a different composition.

Written by: Colin Dundas  (15 February 2021)
 
Acquisition date
10 January 2021

Local Mars time
15:10

Latitude (centered)
-67.893°

Longitude (East)
207.713°

Spacecraft altitude
247.4 km (153.7 miles)

Original image scale range
49.9 cm/pixel (with 2 x 2 binning) so objects ~150 cm across are resolved

Map projected scale
50 cm/pixel

Map projection
Polarstereographic

Emission angle
6.4°

Phase angle
65.6°

Solar incidence angle
70°, with the Sun about 20° above the horizon

Solar longitude
345.7°, Northern Winter

For non-map projected images
North azimuth:  100°
Sub-solar azimuth:  47.8°
JPEG
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

JP2
Black and white
map-projected   (189MB)

IRB color
map-projected   (114MB)

JP2 EXTRAS
Black and white
map-projected  (116MB)
non-map           (119MB)

IRB color
map projected  (59MB)
non-map           (120MB)

Merged IRB
map projected  (196MB)

Merged RGB
map-projected  (179MB)

RGB color
non map           (114MB)
ADDITIONAL INFORMATION
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products
HiView

NB
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

USAGE POLICY
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/JPL/University of Arizona

POSTSCRIPT
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.