Theon Junior is a lunar impact crater that is located just to the west-southwest of the crater Delambre. It forms a matching pair with Theon Senior, only a couple of crater diameters to the north-northwest. The crater is circular and bowl-shaped, with a small floor at the bottom of the high, sloping interior walls. It is named for Theon of Alexandria, a 4th-century Greek astronomer and mathematician.[1] The crater is from the Eratosthenian period, which lasted from 3.2 to 1.1 billion years ago. It is 17 kilometers in diameter and the difference in height at its rim and its deepest part is 3,580 meters.[2][3]
 Lunar Orbiter 4 image of Theon Senior (top) and Theon Junior (bottom) | |
| Coordinates | 2°18′S 15°48′E / 2.3°S 15.8°E |
|---|---|
| Diameter | 17 km |
| Depth | 3,580 m |
| Colongitude | 344° at sunrise |
| Eponym | Theon of Alexandria |
Satellite craters
editBy convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Theon Junior.[4]
| Theon Junior |
Latitude | Longitude | Diameter |
|---|---|---|---|
| B | 2.1° S | 13.3° E | 8 km |
| C | 2.3° S | 14.7° E | 4 km |
References
edit- ^ "Theon Junior (crater)". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
- ^ Autostar Suite Astronomer Edition. CD-ROM. Meade, April 2006.
- ^ Moore, Patrick (2001). On the Moon. Sterling Publishing Co.. ISBN 0-304-35469-4.
- ^ Bussey, B.; Spudis, P. (2004). The Clementine Atlas of the Moon. New York: Cambridge University Press. ISBN 0-521-81528-2.
External links
edit
- Theon Junior at The Moon Wiki
- Wood, Chuck (December 12, 2006). "How Deep is That Hole". Lunar Photo of the Day. Archived from the original on June 14, 2011. - includes a couple of craters such as Theon Junior