Stefan (crater)

Stefan
	Oblique Lunar Orbiter 5 image, facing west
Coordinates	46°00′N108°18′W / 46.0°N 108.3°W Coordinates: 46°00′N108°18′W / 46.0°N 108.3°W
Diameter	125 km
Depth	Unknown
Colongitude	110° at sunrise
Eponym	Joseph Stefan

Last updated August 07, 2019

LRO mosaic Stefan crater LRO.jpg — LRO mosaic

Stefan is a lunar impact crater on the far side of the Moon, just beyond the northwestern limb. Attached to the western rim is the slightly smaller crater Wegener, and close to the eastern rim is Rynin.

Lunar craters are impact craters on Earth's Moon. The Moon's surface has many craters, almost all of which were formed by impacts.

An impact crater is an approximately circular depression in the surface of a planet, moon, or other solid body in the Solar System or elsewhere, formed by the hypervelocity impact of a smaller body. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters range from small, simple, bowl-shaped depressions to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth.

Earth's Moon is an astronomical body that orbits the planet and acts as its only permanent natural satellite. It is the fifth-largest satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits. The Moon is, after Jupiter's satellite Io, the second-densest satellite in the Solar System among those whose densities are known.

As with many craters of this size on the Moon, the outer rim has been worn by impact erosion and the edge and inner wall are generally pitted with small craterlets. The southern edge of the rim in particular has been damaged by impacts, and is overlain by the satellite crater Stefan L. This bowl-shaped crater lies at the center of a small ray system, which is indicative of a relatively young impact.

A ray system comprises radial streaks of fine ejecta thrown out during the formation of an impact crater, looking somewhat like many thin spokes coming from the hub of a wheel. The rays may extend for lengths up to several times the diameter of their originating crater, and are often accompanied by small secondary craters formed by larger chunks of ejecta. Ray systems have been identified on the Moon, Earth, Mercury, and some moons of the outer planets. Originally it was thought that they existed only on planets or moons lacking an atmosphere, but more recently they have been identified on Mars in infrared images taken from orbit by 2001 Mars Odyssey's thermal imager.

The interior floor of Stefan is a generally level surface that is marked by several impacts. The most notable is a ring-shaped crater rim projecting up through the southern half of the floor. Near the midpoint is a low hill, possibly the buried remnant of a central peak.

Stefan lies at the approximate margin of the Coulomb-Sarton Basin, a 530 km wide impact crater of Pre-Nectarian age.

The Coulomb-Sarton Basin is a Pre-Nectarian impact basin on the far side of the moon. It is named after the crater Coulomb northeast of the center of the basin and the smaller crater Sarton just south of the center. The basin is not obvious on the lunar surface. There are only small fragments of inner rings and a rim, and the most indicative topographic feature is a smooth, low plain at the center.

The pre-Nectarian period of the lunar geologic timescale runs from 4.533 billion years ago to 3.920 billion years ago, when the Nectaris Basin was formed by a large impact. It is followed by the Nectarian period.

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 Stefan.

Stefan	Latitude	Longitude	Diameter
L	44.6° N	107.7° W	26 km

Related Research Articles

Bianchini is a lunar impact crater that lies along the northern Jura Mountains that ring the Sinus Iridum, in the northwestern part of the near side of the Moon. It was named after Italian astronomer Francesco Bianchini. The impact of this crater near the edge of the Jura Mountains deposited some material into the Sinus Iridum floor.

Asclepi is a heavily eroded lunar impact crater that lies in the rugged southern highlands of the Moon. The outer rim has been worn down and rounded by many millions of years of subsequent impacts, so that it is now nearly level with the surrounding terrain. As a result, the crater is now little more than a depression in the surface. The interior is nearly flat and relatively featureless.

Büsching is a lunar impact crater that is located in the crater-covered southern highlands of the Moon. It was named after German geographer Anton F. Büsching. The similar-sized crater Buch is located adjacent to its southwestern rim, and further to the southwest lies Maurolycus.

Fabry is a large lunar impact crater of the form termed a walled plain. It is located on the far side of the Moon, just beyond the northeastern limb. Parts of this area are sometimes brought into view by the effects of libration, but the terrain is seen from the edge and so not much in the way of detail can be observed.

Casatus is a lunar impact crater that is located near the southern limb of the Moon. The north-northeast rim of the crater overlies a portion of the slightly larger crater Klaproth. Along the western rim, Casatus A intrudes somewhat into the interior, producing an inward-bowing rim. To the southeast of Casatus is Newton.

Demonax is a lunar impact crater near the southern limb of the Moon. This location makes the crater difficult to observe due to foreshortening. The crater is also illuminated at a very low angle, when it is in the sunlit side. Demonax lies just to the north of the crater Scott, one of the south polar formations. To the north-northwest is Boguslawsky.

Chebyshev is a large lunar impact crater that lies in the southern hemisphere on the far side of the Moon. The somewhat smaller crater Langmuir is intruding into the east-southeastern rim of Chebyshev, forming a chain of large craters with Brouwer on Langmuir's eastern rim.

Carver is a lunar impact crater that is located on the far side of the Moon, due east of the walled plain Van der Waals. To the northeast is the crater Rosseland, and to the south-southeast lies Kozyrev.

Carnot is a large crater in the northern part of the Moon's far side. It intrudes into the southern rim of the huge walled plain Birkhoff. To the west-southwest of Carnot is the crater Paraskevopoulos.

Chappell is a lunar impact crater that is located on the far side of the Moon, in the northern hemisphere just to the north of the crater Debye. This feature is located in a heavily bombarded section of the surface, and much of the outer rim of the crater is overlain by many smaller craters. The northern rim in particular has been almost completely disintegrated, while small craters also overlie the rim to the northwest and southeast. What remains of the rim forms a rounded, somewhat irregular edge to the crater depression.

Chevallier is a lunar impact crater that is located in the northeastern part of the Moon's near side, about a crater diameter east-southeast of the prominent crater Atlas. To the south-southeast of Chevallier is the flooded crater Shuckburgh.

Douglass is a lunar impact crater on the far side of the Moon. It lies to the southwest of the crater Frost and south-southwest of the large walled plain Landau.

Donner is a lunar impact crater on the far side of the Moon. It is located just to the northeast of the Mare Australe, behind the southeastern limb of the Moon. During favorable librations this part of the lunar surface can be brought into view of the Earth, but the site is viewed from the edge and so not much detail can be seen.

Eijkman is a lunar impact crater that is located on the far side of the Moon's southern hemisphere. It lies about a half crater diameter to the southeast of the larger crater Lemaître. To the south-southwest is the crater Crommelin, and to the northeast is Fizeau.

Gullstrand is a lunar impact crater that lies on the northern hemisphere on the Moon's far side. About one crater diameter to the southeast is the larger crater Perrine. To the west-southwest is Quetelet.

Rynin is a lunar impact crater that is located just behind the northwestern limb, on the far side of the Moon. It is located just to the east of the larger crater Stefan, and to the southwest of Chapman.

Kurchatov is a lunar impact crater that is located on the Moon's far side. It is just to the southwest of the crater Wiener, and farther to the southeast of Bridgman. A couple of crater diameters to the south of Kurchatov is the northern edge of the Mare Moscoviense.

Pavlov is a lunar impact crater on the far side of the Moon, approximately 143 kilometers in diameter. Located just to the north-northeast of it is the crater Levi-Civita while to the southeast is Jules Verne.

Mitra is a lunar impact crater that is attached to the western outer rim of the larger crater Mach, on the far side of the Moon. Just to the west of Mitra is Bredikhin, and to the south-southeast lies Henyey. It is named after Sisir Kumar Mitra.

Röntgen is a relatively large lunar impact crater that lies along the northwestern limb of the Moon. Its northwestern outer rim is partly overlain by the crater Nernst. Both Nernst and Röntgen overlie the eastern rim of the much larger walled plain Lorentz. The smaller crater Aston is separated from the eastern edge of Röntgen by only a few kilometers of terrain. To the south-southeast is Voskresenskiy.

References

Andersson, L. E.; Whitaker, E. A. (1982). NASA Catalogue of Lunar Nomenclature. NASA RP-1097.
Blue, Jennifer (July 25, 2007). "Gazetteer of Planetary Nomenclature". USGS . Retrieved 2007-08-05.
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McDowell, Jonathan (July 15, 2007). "Lunar Nomenclature". Jonathan's Space Report . Retrieved 2007-10-24.
Menzel, D. H.; Minnaert, M.; Levin, B.; Dollfus, A.; Bell, B. (1971). "Report on Lunar Nomenclature by the Working Group of Commission 17 of the IAU". Space Science Reviews. 12 (2): 136–186. Bibcode:1971SSRv...12..136M. doi:10.1007/BF00171763.
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Ewen Adair Whitaker was a British-born astronomer who specialized in lunar studies. During World War II he was engaged in quality control for the lead sheathing of hollow cables strung under the English Channel as part of the "Pipe Line Under The Ocean" Project (PLUTO) to supply gasoline to Allied military vehicles in France. After the war, he obtained a position at the Royal Greenwich Observatory working on the UV spectra of stars, but became interested in lunar studies. As a sideline, Whitaker drew and published the first accurate chart of the South Polar area of the Moon in 1954, and served as director of the Lunar Section of the British Astronomical Association.

The National Aeronautics and Space Administration is an independent agency of the United States Federal Government responsible for the civilian space program, as well as aeronautics and aerospace research.

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility.

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Oblique Lunar Orbiter 5 image, facing west
Coordinates	46°00′N108°18′W / 46.0°N 108.3°W / 46.0; -108.3 Coordinates: 46°00′N108°18′W / 46.0°N 108.3°W / 46.0; -108.3
Diameter	125 km
Depth	Unknown
Colongitude	110° at sunrise
Eponym	Joseph Stefan