Gully Monitoring on Crater Slopes in Terra Sirenum
NASA/JPL/University of Arizona
Gully Monitoring on Crater Slopes in Terra Sirenum
ESP_027343_1410  Science Theme: Mass Wasting Processes
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These crater gullies lie on the northern wall of an unnamed 9-kilometer diameter southern hemisphere crater in Terra Sirenum. The image was acquired during early winter in the southern hemisphere, so the crater wall is in shadow.

These gullies were first imaged by HiRISE in 2006. Since that time the possible role of seasonal frost in gully formation along with the association of polygonal terrain with these and other gullies has garnered considerable interest. As a result, these gullies have become one of several locations being monitored by HiRISE throughout multiple Mars years. Over a dozen images of these gullies have been acquired to date throughout different Mars seasons.

In this image, frost (likely water-ice) is once again forming on these southern hemisphere mid-latitude crater slopes. The subimage shows gullies on the shadowed polar-facing slope. The large dynamic range of the HiRISE camera allows one to see into the shadows dimly lit by sunlight scattered by the surface and the atmosphere. These gullies are thinly veiled with frost and range in width from several meters to tens of meters and in length from a couple kilometers or so. Dark regions within the gullies are warmer areas where frost likely evaporated or melted exposing the darker underlying surface.

Written by: Ginny Gulick (audio by Tre Gibbs)  (18 July 2012)
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Acquisition date
27 May 2012

Local Mars time:

Latitude (centered)

Longitude (East)

Range to target site
251.3 km (157.1 miles)

Original image scale range
50.3 cm/pixel (with 2 x 2 binning) so objects ~151 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle:

Phase angle:

Solar incidence angle
78°, with the Sun about 12° above the horizon

Solar longitude
116.1°, Northern Summer

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  47.8°
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Black & white is 5 km across; enhanced color about 1 km
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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

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.