Davy is a small

lunar Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * ''Lunar'' (series), a series of video games * "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior t ...

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...

that is located on the eastern edge of the

Mare Nubium Mare Nubium (Latin ''nūbium'', the "sea of clouds") is a lunar mare in the Nubium basin on the Moon's near side. The mare is located just to the southeast of Oceanus Procellarum. Formation The basin containing Mare Nubium is believed to ha ...

. It was named after British physicist

Humphry Davy Sir Humphry Davy, 1st Baronet, (17 December 177829 May 1829) was a British chemist and inventor who invented the Davy lamp and a very early form of arc lamp. He is also remembered for isolating, by using electricity, several elements for t ...

. It overlies the

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

-flooded remains of the satellite crater Davy Y to the east, a formation which contains a

crater chain A crater chain is a line of craters along the surface of an astronomical body. The descriptor term for crater chains is catena , plural catenae (Latin for "chain"), as specified by the International Astronomical Union's rules on planetary nome ...

designated Catena Davy. To the southeast of Davy is the prominent crater Alphonsus. The outer rim of Davy is low, and the interior has been partly resurfaced. The perimeter is somewhat

polygon In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed ''polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two toge ...

al in shape, especially in the western half, and the southeast rim has been overlain by Davy A. The latter is bowl-shaped with a notch in the northern rim. The interior of Davy lacks a central peak, although there are some low central mounds and the rim of Davy Y forms a low ridge leading from the northern outer rim.

Catena Davy

This linear string of 23 tiny craters runs from the midpoint of Davy Y towards the walled basin

Ptolemaeus Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...

, following a slightly curving course to the east-northeast. It is located at selenographic

coordinate In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space. The order of the coordinates is sign ...

s 11.0° S, 7.0° W, and has a length of 50 km. This formation is not believed to be due to secondary cratering because it is not radial to a suitable source crater. The most likely cause is believed to be a single body that broke apart prior to impact due to tidal effects. High resolution images have demonstrated that the craters formed at about the same time since the

ejecta Ejecta (from the Latin: "things thrown out", singular ejectum) are particles ejected from an area. In volcanology, in particular, the term refers to particles including pyroclastic materials (tephra) that came out of a volcanic explosion and magma ...

from each crater does not overlay neighboring craters. However, there are still some scientists who believe that this chain of craters may be

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

in origin. In 1974, six of the craters in the chain were given "unofficial" names for use in connection with NASA's Topophotomap 77D1S1(10). These names, listed below, were later adopted by the

IAU The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...

. Their positions in the chain are not readily distinguished based on their official

s, but they are well identified on the topophotomap. Catena Davy was considered as a possible early

Apollo Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label=Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label= ...

landing site.To A Rocky Moon
1993, by

Don Wilhelms Don Edward Wilhelms (born July 5, 1930) is a former United States Geological Survey geologist who contributed to geologic mapping of the Earth's moon and to the geologic training of the Apollo astronauts. He is the author of '' To a Rocky Moon: A ...

. PDF version available from L&PI. Chapter 13, p. 245.

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 Davy.

References

* * * * * * * * * * * *

External links

Topophotomap 77D1S1(10)
showing location of minor named features.
Lunar Orbiter map and photo of Alphonsus
shows relationship of Davy to Alphonsus and Ptolemeus. * * * * * * Impact craters on the Moon {{Craters on the Moon: C-F