Coalescing Secondaries

A chain of impact features provides a picturesque tableau (48.659°N; 103.299°E). LROC Narrow Angle Camera (NAC) frame M18286833R, LRO orbit 12051, February 3, 2012; illumination is from the southwest (angle of incidence 63.07°), north is up, image field of view approximately 2 km across [NASA/GSFC/Arizona State University].

James Ashley
LROC News System

Today's Feature Image exhibits a chain of impact features that are so closely spaced as to lose their distinction as separate landforms, producing one continuous feature instead.

An asymmetry in the ejecta pattern can also be seen in the form of filamentary tendrils extending to the north.

Based on this ejecta distribution, the secondary bolides likely came from a southerly or southeasterly direction.

Another, earlier look at the same field of view, at slightly higher resolution. LROC NAC M123901314R, orbit 3393, March 22, 2010; angle of incidence 47.54° at 0.56 meters resolution from 53.96 km [NASA/GSFC/Arizona State University].

The WAC mosaic context image is approximately 83 km wide [NASA/GSFC/Arizona State University].

Zooming out to learn what this source might have been produces no obvious candidates, however. None of the medium-sized craters within 40 km of the featured crater chain appear to be particularly young -- a condition required to explain the chain's fresh appearance. Not until we expand our view even further do likely candidates crop up.

This larger scale WAC mosaic context image is just about 470 km wide [NASA/GSFC/Arizona State University].

But even here nothing unambiguous catches the eye. The secondary impacts could have resulted from one of any number of craters, or perhaps from an impact located even further away. A detailed surface study would be necessary before a definitive link could be made tying this ejecta with its crater of origin. Explore the full NAC frame HERE.

Other examples of ejecta interactions with the lunar surface can be found in Crater Chain near Rima T Mayer, Four of a Kind in Catena Davy, and Four Leaf Clover.

Bonus Context: The location of the field of view shown at high resolution in the LROC Featured Image, released May 29, 2013 in the north farside highlands. The terrain is representative of one of the four recognized lunar material groups, the farside anorthositic highland terrain, or FaHT [NASA/GSFC/SVS].