Theon Senior (crater)
Encyclopedia
Theon Senior is a lunar
impact crater
that is located to the northwest of the crater Delambre
, and south of D'Arrest
. It forms a matching pair with Theon Junior
, about two crater diameters to the south-southeast. The satellite crater Theon Senior A can be found to the north. Theon Senior is named for Theon of Smyrna, a 1st-century Greek mathematician and philosopher.
This crater is circular and bowl-shaped, with only a small floor at the center of the steeply sloping interior walls. The crater appears relatively young, as it shows little sign of wear due to impacts. The crater is about 18 kilometers in diameter, and the distance from its rim to the floor is 3470 meters. Theon Senior is from the Eratosthenian
period, which lasted from 3.2 to 1.1 billion years ago.
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
that is located to the northwest of the crater Delambre
Delambre (crater)
Delambre is a lunar impact crater that lies to the southwest of Mare Tranquillitatis, in the central highland region. To the west is the crater pair of Theon Junior and Theon Senior, the latter being more distant and located to the northwest. It is 52 kilometers in diameter and 3.5 kilometers in...
, and south of D'Arrest
D'Arrest (crater)
D'Arrest is a lunar crater that is located in the lava-flooded region to the west of the Mare Tranquillitatis. It lies to the southeast of the crater Agrippa and northwest of Delambre...
. It forms a matching pair with Theon Junior
Theon Junior (crater)
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,...
, about two crater diameters to the south-southeast. The satellite crater Theon Senior A can be found to the north. Theon Senior is named for Theon of Smyrna, a 1st-century Greek mathematician and philosopher.
This crater is circular and bowl-shaped, with only a small floor at the center of the steeply sloping interior walls. The crater appears relatively young, as it shows little sign of wear due to impacts. The crater is about 18 kilometers in diameter, and the distance from its rim to the floor is 3470 meters. Theon Senior is from the Eratosthenian
Eratosthenian
The Eratosthenian period in the lunar geologic timescale runs from 3,200 million years ago to 1,100 million years ago. It is named after the crater Eratosthenes, whose formation marks the beginning of this period. The formation of the crater Copernicus marks its end, and the beginning of the...
period, which lasted from 3.2 to 1.1 billion years ago.
Satellite craters
By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Theon Senior.| Theon Senior |
Latitude | Longitude | Diameter |
|---|---|---|---|
| A | 0.2° S | 15.4° E | 5 km |
| B | 0.2° N | 14.1° E | 6 km |
| C | 1.4° S | 14.5° E | 6 km |