Theon Junior (crater)

Theon Junior
Lunar Orbiter 4 image of Theon Senior (top) and Theon Junior (bottom)
Coordinates2°18′S 15°48′E / 2.3°S 15.8°E / -2.3; 15.8
Diameter17 km
Depth3,580 m
Colongitude344° at sunrise
EponymTheon of Alexandria
The crater area in a Selenochromatic format Image (Si)
Oblique view of Theon Senior (top) and Theon Junior (bottom) from Apollo 16

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]

  1. ^ "Theon Junior (crater)". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
  2. ^ Autostar Suite Astronomer Edition. CD-ROM. Meade, April 2006.
  3. ^ Moore, Patrick (2001). On the Moon. Sterling Publishing Co.. ISBN 0-304-35469-4.