Geminus (crater)

Geminus
	LRO mosaic
Coordinates	34°25′N 56°40′E / 34.42°N 56.66°E
Diameter	81.98 km (50.94 mi)
Depth	5.4 km
Colongitude	304° at sunrise
Formation	Eratosthenian
Eponym	Geminus

Geminus is a lunar impact crater that is located near the northeast limb of the visible Moon. In this position the crater appears oval in shape due to foreshortening, but it is actually more nearly circular in form. It was named by the IAU in 1935.^[2]

This formation is dated to the Eratosthenian period of the lunar geologic timescale.^[1] The circular rim of Geminus contain a number of outward notches, particularly to the north and east. The crater ejecta is still visible in the rough surroundings beyond the rim, but any rays deposited during the impact have long since been worn away by space weathering. The inner wall is wide and extensively terraced, although these features are now somewhat muted due to impact erosion.

There are no notable impacts on the interior floor, but there is a long, slender central ridge located at the midpoint and a pair of readily observed clefts. The infrared spectrum of pure crystalline plagioclase has been identified on this rise and the western floor.^[3]

Notable nearby craters include Messala to the northeast, Bernoulli due east, and Burckhardt and Cleomedes to the south.^[4]

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 Geminus.

Geminus	Latitude	Longitude	Diameter
A	31.5° N	51.8° E	15 km
B	34.2° N	52.3° E	10 km
C	33.9° N	58.7° E	16 km
D	30.6° N	47.4° E	16 km
E	33.5° N	48.5° E	67 km
F	32.1° N	51.1° E	22 km
G	30.8° N	48.6° E	14 km
H	31.6° N	48.9° E	15 km
M	31.9° N	48.5° E	11 km
N	31.4° N	47.7° E	24 km
W	34.3° N	47.4° E	6 km
Z	30.7° N	46.7° E	26 km

References

1 2 Kirchoff, Michelle R.; et al. (July 2013). "Ages of large lunar impact craters and implications for bombardment during the Moon's middle age". Icarus. 225 (1): 325–341. Bibcode:2013Icar..225..325K. doi:10.1016/j.icarus.2013.03.018. USGS epoch.
↑ "Geminus". Gazetteer of Planetary Nomenclature. IAU/NASA/USGS. Retrieved 28 April 2024.
↑ Donaldson Hanna, K. L.; et al. (July 2014). "Global assessment of pure crystalline plagioclase across the Moon and implications for the evolution of the primary crust". Journal of Geophysical Research: Planets. 119 (7): 1516–1545. Bibcode:2014JGRE..119.1516D. doi:10.1002/2013JE004476.
↑ Webb, Rev. T. W. (1962). Celestial Objects for Common Telescopes (6th revised ed.). Dover. pp. 107, 154–159. Reprint: ISBN 978-0-486-20917-3

Sources

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.
Bussey, B.; Spudis, P. (2004). The Clementine Atlas of the Moon. New York: Cambridge University Press. ISBN 978-0-521-81528-4.
Cocks, Elijah E.; Cocks, Josiah C. (1995). Who's Who on the Moon: A Biographical Dictionary of Lunar Nomenclature. Tudor Publishers. ISBN 978-0-936389-27-1.
McDowell, Jonathan (July 15, 2007). "Lunar Nomenclature". Jonathan's Space Report. Archived from the original on 2012-02-08. 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. S2CID 122125855.
Moore, Patrick (2001). On the Moon. Sterling Publishing Co. ISBN 978-0-304-35469-6.
Price, Fred W. (1988). The Moon Observer's Handbook. Cambridge University Press. ISBN 978-0-521-33500-3.
Rükl, Antonín (1990). Atlas of the Moon. Kalmbach Books. ISBN 978-0-913135-17-4.
Whitaker, Ewen A. (1999). Mapping and Naming the Moon. Cambridge University Press. ISBN 978-0-521-62248-6.
Wlasuk, Peter T. (2000). Observing the Moon. Springer. ISBN 978-1-85233-193-1.

[Kirchoff_et_al_2013-1] 1 2 Kirchoff, Michelle R.; et al. (July 2013). "Ages of large lunar impact craters and implications for bombardment during the Moon's middle age". Icarus. 225 (1): 325–341. Bibcode:2013Icar..225..325K. doi:10.1016/j.icarus.2013.03.018. USGS epoch.

[gpn-2] "Geminus". Gazetteer of Planetary Nomenclature. IAU/NASA/USGS. Retrieved 28 April 2024.

[Donaldson_Hanna_et_al_2014-3] Donaldson Hanna, K. L.; et al. (July 2014). "Global assessment of pure crystalline plagioclase across the Moon and implications for the evolution of the primary crust". Journal of Geophysical Research: Planets. 119 (7): 1516–1545. Bibcode:2014JGRE..119.1516D. doi:10.1002/2013JE004476.

[Webb_1962-4] Webb, Rev. T. W. (1962). Celestial Objects for Common Telescopes (6th revised ed.). Dover. pp. 107, 154–159. Reprint: ISBN 978-0-486-20917-3

[1]

[2]

[3]

[4]

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