Dust-Mantled Topography near Zephyria Tholus
Dust-Mantled Topography near Zephyria Tholus
ESP_016954_1590  Science Theme: Volcanic Processes
This image covers some high-standing topography just outside the rim of an approximately 30 kilometer diameter impact crater. What formed this hill? Could it be a volcano? That was hypothesized to be the case in a paper published in 2001, and this suggestion was entered to test that idea, perhaps from seeing internal layering exposed by the crater.

This is an example of what we regard as an excellent science justification—following up on a testable hypothesis with specific observational goals. It was entered by blogospherian Emily Lakdawalla of the Planetary Society. If you’re thinking we chose to acquire this image early because we want her to blog nice things about HiRISE and HiWiSH, you're right! But its also a good suggestion.

So what does the HiRISE image show us? Mostly it shows a dust mantle, hiding the bedrock it was intended to study. The dustiness is especially apparent from the uniformity of the color data. Much of Mars is covered by dust, so we often favor the relatively dust-free patches for HiRISE imaging. (You can usually tell whether a surface is dusty by looking at
dust index maps and the THEMIS nighttime IR mosaic.) We hope to get the nighttime IR map entered as a layer of HiWISH to help image suggesters.

The night-IR bright (warm) stuff is rocky or sandy, and dark (cool) stuff is probably dusty. Dust cools off rapidly at night while rocks store and slowly release heat. If the dust is thin, HiRISE images can still show the underlying meter-scale morphology. Maybe someone will want to study the dust-related processes on Mars, which are actually not well understood. Additionally, dusty surfaces are where we can find new impact craters that disturb the dust and make easy-to-see dark spots. We’ll see if Emily finds something interesting in this image.

Written by: Alfred McEwen  (31 March 2010)
Acquisition date
09 March 2010

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
257.2 km (159.9 miles)

Original image scale range
51.4 cm/pixel (with 2 x 2 binning) so objects ~154 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
63°, with the Sun about 27° above the horizon

Solar longitude
61.7°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  46.3°
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

Black and white
map-projected   (378MB)

IRB color
map-projected   (197MB)

Black and white
map-projected  (175MB)
non-map           (179MB)

IRB color
map projected  (54MB)
non-map           (209MB)

Merged IRB
map projected  (329MB)

Merged RGB
map-projected  (301MB)

RGB color
non map           (192MB)
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

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.