Alpetragius is a
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 ...
located on the eastern edge of
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 ...
, to the southwest of the much larger crater
Alphonsus. In the southeast is the prominent crater
Arzachel, and to the west lies the flooded
Lassell. Alpetragius is a Latinization of the name of
Nur ad-Din al-Bitruji, a Spanish-Arab astronomer.
The most notable feature of this crater is the disproportionately large central peak, which forms a rounded rise that occupies almost the entire crater floor—one-third the crater diameter—and rises to a height of 2.0 km. There is evidence that this peak has been enlarged through
volcanic eruptions
Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often ...
, and there appears to be an eroded vent at its summit. The rim has fine terraces that slope down to near the edge of the central rise along the south and east sides. This outer wall is nearly round, with slight protrusions on the north and west sides.
The outer rim is joined to the southwest rim of Alphonsus by a rise in the surface. An arc of craterous depressions from the south rim of Alphonsus curves to the west, dividing Alpetragius from Arzachel crater. To the west-northwest is the crater-like outline of Alpetragius X, now flooded by the
mare
A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than four ...
and overlain across the east by ejecta from Alpetragius. Alpetragius is similar in appearance to
Behaim
Martin Behaim (6 October 1459 – 29 July 1507), also known as and by various forms of , was a German textile merchant and cartographer. He served John II of Portugal as an adviser in matters of navigation and participated in a voyage to W ...
crater, although Behaim is larger.
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 Alpetragius.
References
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External links
Debris Channels at Alpetragius B
Related articles
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Impact craters on the Moon
{{Craters on the Moon: A–B