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Billy (crater)

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Billy
Lunar Orbiter 4 image
(spots at upper right are blemishes on original)
Coordinates13°48′S 50°06′W / 13.8°S 50.1°W / -13.8; -50.1
Diameter45.57 km (28.32 mi)[1]
Depth1.2 km (0.75 mi)
Colongitude50° at sunrise
FormationNectarian or Early Imbrian[2]
EponymJacques de Billy

Billy is a lunar impact crater that is located at the southern fringes of the Oceanus Procellarum, in the western hemisphere of the Moon. It lies to the southeast of the similar-sized crater Hansteen, and west-southwest of the similar-sized flooded Letronne.[3]

The interior floor of Billy has been flooded by basaltic lava, leaving a dark surface due to the low albedo.[4] This feature makes it easier to identify under high illumination.[3] The portion of the rim remaining above the surface is narrow and low, with a thin inner wall that is somewhat polygonal in outline. Only a few tiny craterlets mark the interior,[5][6]: 74–75  with a pair in the southern half showing gray ejecta collars.[7]

This formation dates to 3.88 ga, placing it in the Nectarian or Early Imbrian epoch of the lunar geologic timescale, with the resurfacing event occurring at 3.86 ga.[2] The ejecta blanket surrounding Billy is relatively rich in FeO and TiO2.[8] To the north of the crater is a triangular mountainous formation named Mons Hansteen, after the nearby crater. Southeast of Billy is a rille, designated Rima Billy,[9] that runs 70 kilometers to the south.

This crater was named after French mathematician Jacques de Billy (1602–1679).[1] The name was incorporated into lunar nomenclature by Italian astronomer Giovanni Riccioli in 1651.[10] Its designation was formally adopted by the International Astronomical Union in 1935.[1]

Satellite craters

[edit]

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Billy.[11]

Billy[6]: 293  Latitude Longitude Diameter
A 14.3° S 46.3° W 7 km
B 12.2° S 47.6° W 25 km
C 16.1° S 49.0° W 6 km
D 14.9° S 48.3° W 11 km
E 15.0° S 49.6° W 2 km
H 15.6° S 49.6° W 3 km
K 12.9° S 48.7° W 4 km

References

[edit]
  1. 1 2 3 "Billy". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
  2. 1 2 Chauhan, Mamta; et al. (December 2018). "Remote spectral-compositional analysis of basalt mineralogy at Hansteen-Billy, Moon". Meteoritics & Planetary Science. 53 (12): 2583–2595. Bibcode:2018M&PS...53.2583C. doi:10.1111/maps.13176.
  3. 1 2 Moore, Patrick (2001). On the Moon. Sterling Publishing Co. p. 192. ISBN 978-0-304-35469-6.
  4. ↑ "Dark lava floor of crater Billy seen by SMART-1". ESA. February 16, 2006. Retrieved March 31, 2006.
  5. ↑ Price, Fred W. (1988). The Moon Observer's Handbook. Cambridge University Press. p. 163. ISBN 978-0-521-33500-3.
  6. 1 2 Bussey, B.; Spudis, P. (2004). The Clementine Atlas of the Moon. New York: Cambridge University Press. ISBN 978-0-521-81528-4.
  7. ↑ Grego, Peter (2005). The Moon and How to Observe It. Astronomers' Observing Guides Series. London: Springer-Verlag. p. 187. ISBN 1-85233-748-6.
  8. ↑ Hawke, B. Ray; et al. (July 2003). "Hansteen Alpha: A volcanic construct in the lunar highlands". Journal of Geophysical Research: Planets. 108 (E7) 5069. Bibcode:2003JGRE..108.5069H. doi:10.1029/2002JE002013.
  9. ↑ toe Laer, Fredrick (2026). The Atlas of the Near Side of the Moon. Springer Nature. pp. 110–111. ISBN 978-3-031-99278-0.
  10. ↑ Whitaker, Ewen A. (1999). Mapping and Naming the Moon. Cambridge University Press. pp. 60, 211. ISBN 978-0-521-62248-6.
  11. ↑ Grego, P. (2015). "Satellite Crater". In Hargitai, H.; Kereszturi, Á. (eds.). Encyclopedia of Planetary Landforms. New York, NY: Springer. pp. 1858–1859. doi:10.1007/978-1-4614-3134-3_328. ISBN 978-1-4614-3133-6.
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