Nanedi Vallis: Tributaries and Albedo Changes
Nanedi Vallis: Tributaries and Albedo Changes
PSP_001508_1850  Science Theme: Composition and Photometry
This HiRISE image shows a part of Nanedi Vallis, one of the Martian valley networks. The valley networks are thought to have formed by flowing water in the distant past when the climate on Mars was warmer and wetter than it is today.

Some scientists have suggested that the valley networks could have been produced in a climate like the dry, cold one of Mars today if the liquid water was protected by an overlying ice layer. Others think that glacial activity may be responsible for them, but the majority believe that the valley networks are evidence of ancient flowing water.

Valley networks are characterized by their blunt, theater-shaped heads and their approximately constant width along their reaches. They often have tributaries, as seen in this image, that connect with the main trunk of the valley.

Written by: Kelly Kolb  (7 February 2007)
Acquisition date
21 November 2006

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
269.1 km (167.2 miles)

Original image scale range
from 26.9 cm/pixel (with 1 x 1 binning) to 107.8 cm/pixel (with 4 x 4 binning)

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
53°, with the Sun about 37° above the horizon

Solar longitude
138.9°, Northern Summer

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  22.4°
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   (462MB)

IRB color
map-projected   (360MB)

Black and white
map-projected  (212MB)
non-map           (190MB)

IRB color
map projected  (104MB)
non-map           (314MB)

Merged IRB
map projected  (143MB)

Merged RGB
map-projected  (146MB)

RGB color
non map           (293MB)
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.