Polybius (crater)

Polybius is a lunar impact crater in the southeast part of the Moon, and is named after ancient Greek historian Polybius.[1] It is located to the south-southeast of the larger crater Catharina, in the area framed by the Rupes Altai scarp. Some distance to the northeast is the Mare Nectaris, with the flooded craters Beaumont and Fracastorius.

Polybius

Lunar Orbiter 4 image
Coordinates	22.4°S 25.6°E
Diameter	41 km
Depth	2.1 km
Colongitude	335° at sunrise
Eponym	Polybius

Location of Polybius

The crater rim of Polybius appears slightly distended in the northeast, and has a cut through the northern wall. But the wall is otherwise moderately intact with only minor erosion. The interior floor is flat and almost featureless, with no central rise. To the south and east, a ray from Tycho cuts across the bowl-shaped Polybius A and Polybius B craterlets.

Satellite craters

Polybius and its satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Polybius.

Polybius	Latitude	Longitude	Diameter
A	23.0° S	28.0° E	17 km
B	25.5° S	25.5° E	12 km
C	22.0° S	23.6° E	29 km
D	26.9° S	27.9° E	9 km
E	24.4° S	26.2° E	9 km
F	22.2° S	23.0° E	21 km
G	22.5° S	22.7° E	5 km
H	21.1° S	22.7° E	8 km
J	22.7° S	23.5° E	9 km
K	24.3° S	25.3° E	14 km
L	22.0° S	28.2° E	7 km
M	21.3° S	22.1° E	6 km
N	23.4° S	26.8° E	13 km
P	21.5° S	22.9° E	17 km
Q	25.1° S	27.5° E	6 km
R	25.6° S	27.3° E	7 km
T	26.1° S	25.5° E	12 km
V	25.2° S	29.1° E	6 km

Polybius K is sometimes referred to as "Larrieu’s Dam" because the unusually straight northwest rim of the crater creates the appearance of a dam under certain lighting conditions.[2]

• 
  Polybius K crater

References

1. "Gazetteer of Planetary Nomenclature | Polybius". usgs.gov. International Astronomical Union. Retrieved August 24, 2017.
2. ‘Larrieu’s Dam’; the ‘rediscovery’ of a seldom explored topographical lunar feature in the foothills of the Rupes Altai. Nigel Longshaw. J. Br. Astron. Assoc. 118, 2, 2008.

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