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An Intriguing Dark Halo
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An Intriguing Dark Halo
Release Date: October 9, 2008
Topics: Craters with Dark Material, Derain, Mercury Flyby 2, ,

Update: This crater featuring dark material was given the name Derain in July 2009.

Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774051
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 540 meters/pixel (0.34 miles/pixel) on the left side of the image
Scale: This image is about 550 kilometers tall (340 miles)
Spacecraft Altitude: 21,200 kilometers (13,100 miles)

Of Interest: A crater discovered in the newly imaged portion of Mercury°s surface during MESSENGER°s second Mercury flyby has uncommonly dark material within and surrounding the crater. The material is darker than the neighboring terrain such that this crater with a diameter of 180 kilometers (110 miles) is easily identified even in a distant global image of Mercury; it is located just south of the equator near the limb of the planet in this previously released Wide Angle Camera (WAC) image. The dark halo may be material with a mineralogical composition different from the majority of Mercury°s visible surface. Craters with similar dark material on or near their rims were seen on the floor of the Caloris basin during MESSENGER°s first flyby. Images acquired though the 11 different narrow-band color filters of the WAC during MESSENGER°s second flyby will be crucial to an understanding of the nature of this newly seen, unusual feature.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

For information regarding the use of MESSENGER images, see the image use policy.

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