Davy is a small lunar

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...

 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 on the eastern edge of the Mare Nubium

Mare Nubium

Mare Nubium 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. The actual basin is believed to be of Pre-Nectarian system, with the surrounding basin material being of the Lower Imbrian epoch. The mare material is of the...

. It overlies the lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

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

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 , as specified by the International Astronomical Union's rules on planetary nomenclature....

 designated Catena Davy. To the southeast of Davy is the prominent crater Alphonsus

Alphonsus (crater)

Alphonsus is an ancient impact crater on the Moon that dates from the immediate post-Nectarian era. It is located on the lunar highlands on the eastern end of Mare Nubium, west of the Imbrian Highlands, and slightly overlaps the crater Ptolemaeus to the north. The surface is broken and irregular...

.

The outer rim of Davy is low, and the interior has been partly resurfaced. The perimeter is somewhat polygon

Polygon

In geometry a polygon is a flat shape consisting of straight lines that are joined to form a closed chain orcircuit.A polygon is traditionally a plane figure that is bounded by a closed path, composed of a finite sequence of straight line segments...

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 mid-point of Davy Y towards the walled basin Ptolemaeus

Ptolemaeus (lunar crater)

Ptolemaeus is an ancient lunar impact crater close to the center of the near side. To the south-southeast Ptolemaeus is joined to the rim of the crater Alphonsus by a section of rugged, irregular terrain, and these form a prominent chain with Arzachel to the south...

, following a slightly curving course to the east-northeast. It is located at selenographic coordinates 11.0° S, 7.0° W, and has a diameter 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 due to 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

Ejecta can mean:*In volcanology, particles that came out of a volcanic vent, traveled through the air or under water, and fell back on the ground surface or on the ocean floor...

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

International Astronomical Union

The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...

. Their positions in the chain are not readily distinguished based on their official coordinates, but they are well identified on the topophotomap.

Crater	Coordinates	Diameter	Name source
Alan	10.9°S 6.1°W	2.0 km	Irish Irish language Irish , also known as Irish Gaelic, is a Goidelic language of the Indo-European language family, originating in Ireland and historically spoken by the Irish people. Irish is now spoken as a first language by a minority of Irish people, as well as being a second language of a larger proportion of...  masculine name
Delia	10.9°S 6.1°W	2.0 km	Greek Greek language Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...  feminine name
Harold	10.9°S 6.0°W	2.0 km	Scandinavia Scandinavia Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,... n masculine name
Osman	11.0°S 6.2°W	2.0 km	Turkish Turkish language Turkish is a language spoken as a native language by over 83 million people worldwide, making it the most commonly spoken of the Turkic languages. Its speakers are located predominantly in Turkey and Northern Cyprus with smaller groups in Iraq, Greece, Bulgaria, the Republic of Macedonia, Kosovo,...  masculine name
Priscilla	10.9°S 6.2°W	1.8 km	Latin Latin Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...  feminine name
Susan	11.0°S 6.3°W	1.0 km	English English language English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria... feminine name

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 Davy.

Davy	Latitude	Longitude	Diameter
A	12.2° S	7.7° W	15 km
B	10.8° S	8.9° W	7 km
C	11.2° S	7.0° W	3 km
G	10.4° S	5.1° W	16 km
K	10.2° S	9.5° W	3 km
U	12.9° S	7.1° W	3 km
Y	11.0° S	7.1° W	70 km

External links

• Topophotomap 77D1S1(10) showing location of minor named features.
• Davy from NASA / Brown.
• Lunar Orbiter map and photo of Alphonsus, shows relationship of Davy to Alphonsus and Ptolemeus.
• Moon map showing position of nearby Alphonsus.