Butterfly Ejecta around a Fresh Crater
Butterfly Ejecta around a Fresh Crater
ESP_018094_1720  Science Theme: Impact Processes
The approximately 650-meter (2135 foot) diameter crater in this image is relatively fresh, as evidenced by its sharp rim and unmodified shape. Ejecta appears on top of pre-existing craters, and stands out against the background, again indicating relative youth.

However, there is something else interesting about the ejecta for this crater. It is butterfly-shaped, with much more expansive ejecta along one axis, and much less along the perpendicular axis.

Butterfly-shaped ejecta indicate that the body that caused the crater struck Mars at an oblique (or very shallow) angle. When this happens, the crater shape may be elliptical, although round craters can result from oblique impacts, too. During an oblique impact, much more ejecta is thrown out perpendicular to the direction of impact, and relatively little material is ejected along the impactor’s trajectory. Oblique impacts are relatively rare, and so a fresh, oblique impact like this one is an attractive target.

Written by: Nicole Baugh  (30 June 2010)
Acquisition date
06 June 2010

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
264.9 km (164.6 miles)

Original image scale range
26.5 cm/pixel (with 1 x 1 binning) so objects ~80 cm across are resolved

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
100.8°, Northern Summer

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  41.1°
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Black & white is 5 km across; enhanced color about 1 km
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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.