Diophantus (crater)

Diophantus is a lunar impact crater that lies in the southwestern part of the Mare Imbrium, named after the ancient Greek mathematician Diophantus.^[1] It forms a pair with the larger crater Delisle to the north, has a wide inner wall and a low central rise. To the north of Diophantus is the sinuous rille designated Rima Diophantus, named after the crater. Diophantus C lies near the exterior of the southwest wall.

Diophantus

Apollo 15 image
Coordinates	27.6°N 34.3°W / 27.6; -34.3
Diameter	19 km
Depth	3.0 km
Colongitude	34° at sunrise
Eponym	Diophantus

Diophantus area (top right) in selenochromatic format holding some normal (yellow)/pyroclastic(red) selenochromatic landmarks

Oblique view of Diophantus from Apollo 17, at low sun angle, with the smaller Diophantus C at left.

High-resolution view of dark streaks in the wall of Diophantus, showing downslope movement of buried subsurface deposits.

The craters Delisle (above) and Diophantus (below) from Apollo 15. Mons Delisle is to the left of Delisle, and Rima Diophantus lies between Delisle and Diophantus. Note also bright rays extending from the tiny crater Samir.

Diophantus is a crater of Eratosthenian age.^[2]

Rima Diophantus

This cleft follows a generally east–west path across the Mare Imbrium. It is centered at selenographic coordinates 31.0° N, 32.0° W, and has a maximum diameter of 150 km.

Small craters

Several tiny craters north of Diophantus have been assigned names by the IAU. These are listed in the table below.

Crater	Coordinates	Diameter	Name source
Isabel	28.2°N 34.1°W / 28.2; -34.1	1 km	Spanish feminine name
Louise	28.5°N 34.2°W / 28.5; -34.2	0.8 km	French feminine name
Samir	28.5°N 34.3°W / 28.5; -34.3	2 km	Arabic masculine name
Walter1	28.0°N 33.8°W / 28.0; -33.8	1 km	German masculine name

1	Not to be confused with the large crater Walther in the southern hemisphere which is misidentified as 'Walter' in some publications

High-resolution image of Samir (left) and Louise from Apollo 15 panoramic camera.

The crater Samir has bright rays that extend for over 70 km.

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 Diophantus.

Diophantus	Latitude	Longitude	Diameter
B	29.1° N	32.5° W	6 km
C	27.3° N	34.7° W	5 km
D	26.9° N	36.3° W	4 km

The following crater has been renamed by the IAU.

• Diophantus A — See Artsimovich.