Diophantus (crater)
Crater on the Moon
From Wikipedia, the free encyclopedia
Diophantus is a small lunar impact crater that lies in the southwestern part of the Mare Imbrium.[4] It forms a pair with the larger crater Delisle to the north.[5] At a similar distance to the west is the smaller Artsimovich crater and the Fedorov feature.[6]
Apollo 15 image | |
| Coordinates | 27.6°N 34.3°W |
|---|---|
| Diameter | 17.57 km (10.92 mi)[1] |
| Depth | 3.02 km (1.88 mi)[2] |
| Colongitude | 34° at sunrise |
| Formation | Eratosthenian[3] |
| Eponym | Diophantus |
On the lunar geologic timescale, Diophantus is a crater of Eratosthenian age.[3] It is a sharp-edged crater with a wide inner wall and a low central rise. It shows no degradation from subsequent impacts.[7]: 39 High resolution imagery of the inner wall show dark streaks, which originate from material exposed by the impact.[8] A skirt of ejecta spreads across the surrounding mare surface.[9] The cup-shaped impact crater Diophantus C lies prominently near the exterior of the southwest wall.[6]
To the north of Diophantus is the sinuous rille designated Rima Diophantus, named after the crater.[10] It is centered at selenographic coordinates 31.0°N 32.0°W, and has a maximum diameter of 201.50 km (125.21 mi).[10] This cleft follows a generally east–west path across the Mare Imbrium.[6] The section nearest Diophantus crater is partially filled with ejecta from that impact.[9]
This formation named after the ancient Greek mathematician Diophantus (unkn-c. A.D. 300). His name was included in the lunar nomenclature of German selenographer Johann H. von Mädler during the 19th century.[11] Its designation was formally adopted by the International Astronomical Union in 1935.[1]
Small craters
Several tiny craters north of Diophantus have been assigned names by the IAU.[6] These are listed in the table below.
| Crater | Coordinates | Diameter | Name source |
|---|---|---|---|
| Isabel | 28.2°N 34.1°W | 1 km | Spanish feminine name |
| Louise | 28.5°N 34.2°W | 0.8 km | French feminine name |
| Samir | 28.5°N 34.3°W | 2 km | Arabic masculine name |
| Walter1 | 28.0°N 33.8°W | 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 |
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.[12]
| Diophantus[7]: 297 | 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.[13]
