Tuesday, May 14, 2013

Swarm of Secondaries on the floor of Crüger

Western portion of Crüger crater floor. LROC Narrow Angle Camera (NAC) mosaic (M1108725909R and M1108725909L), LRO orbit 15669, November 28, 2012, centered near 16.759°S, 292.627°E, field of view 1670 meters, sunlight from the west, angle of incidence 72.32° at 1.67 meters per pixel resolution, from 79.83 km [NASA/GSFC/Arizona State University].
Hiroyuki Sato
LROC News Center

Crüger is a 45 km diameter crater located between Oceanus Procellarum and Orientale basin. The floor is completely covered in basaltic lava deposits, and is very flat. The western portion of the floor shows slightly high reflectance spots with clustered craters and disturbed surfaces, likely a field of secondary craters.

A unique feature of this grouping is the sharp topographic relief delimiting its southern boundary.

The upper half of the opening image, the relatively disturbed and hummocky part, corresponds to the cluster area. Note that the sunlight is from the right side, and the cluster area is topographically lower than the southern relatively smooth area along the delimiting boundary.

LROC NAC context mosaic M1108725909LR showing the Crüger crater floor, a 7.3 km-wide field of view, image centered on 16.736°S, 292.645°E [NASA/GSFC/Arizona State University].
Roughly 20 km-wide field of view from a 62 meter per pixel resolution LROC Wide Angle Camera (WAC) frame shows the 'chevron' of encapsulated secondary craters on the west central floor of 45 km Crüger. LROC WAC observation M129729786C (689 nm), spacecraft orbit 4251, May 28, 2010; angle of incidence 62.36° from 44.57 km [NASA/GSFC/Arizona State University].
WAC monochrome mosaic (100 m/pix) of Crüger crater and surrounding area. Image center is 17.15°S, 293.05°E. Two NAC footprints (blue boxes) and the location of today's Featured Image are indicated here [NASA/GSFC/Arizona State University].
As seen in the NAC context view, the southern end of this secondary cluster is surrounded by this sharp boundary. Likely a densely packed group of ejecta landed with a low angle, resulting in this unique deposition pattern.

Explore this unique secondary crater cluster patterns in full NAC frame yourself, HERE.

Related Posts:
Cluster of farside secondary craters
Stream of Secondary Craters
Chain of secondary craters in Mare Orientale
Regolith on Basalt
Tres Amicis
Crater Chain near Rima T Mayer

No comments: