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Dactyl (moon)

From Simple English Wikipedia, the free encyclopedia

Dactyl (designated (243) Ida I Dactyl) is a tiny asteroid moon which is 1.6 km in diameter and orbits the asteroid 243 Ida in the asteroid belt.[1] It was first imaged by the Galileo spacecraft on August 28, 1993; Dactyl was discovered while examining the delayed image downloads from the Galileo spacecraft on February 17, 1994. It was provisionally designated S/1993 (243) 1. The small moon was named after the mythical creatures called dactyls who lived on Mount Ida according to Greek mythology.[2]

Discovery dateFebruary 17, 1994
Named after
Dactyls (mythology)
Dactyl (Ida I)

Dactyl orbits the asteroid, Ida, with a period of 1.54 days at an average distance of 108 km, with an inclination of 9° to Ida's equator.[3]

Dactyl was the first asteroid moon discovered. Its discovery settled the long discuss over the existence of asteroid moons.

Origin[change | change source]

The origins of Dactyl are unclear, but two main hypotheses exist. The first is that Dactyl and Ida formed at the same time, and the second is that Dactyl was knocked loose by a later impact.[4][5]

References[change | change source]

  1. "Asteroid 243 Ida and its newly discovered moon, Dactyl". www.esa.int. Retrieved 2022-11-13.
  2. "In Depth | 243 Ida". NASA Solar System Exploration. Retrieved 2022-11-13.
  3. Chapman, C. R.; Veverka, J.; Thomas, P. C.; Klaasen, K.; Belton, M. J. S.; Harch, A.; McEwen, A.; Johnson, T. V.; Helfenstein, P.; Davies, M. E.; Merline, W. J. (1995). "Discovery and physical properties of Dactyl, a satellite of asteroid 243 Ida". Nature. 374 (6525): 783–785. doi:10.1038/374783a0. ISSN 1476-4687. S2CID 4319450.
  4. Granahan, James (2002). "A compositional study of asteroid 243 Ida and Dactyl from Galileo NIMS and SSI observations". Journal of Geophysical Research. 107 (E10): 5090. doi:10.1029/2001JE001759. ISSN 0148-0227.
  5. Davis, Donald R.; Chapman, Clark R.; Durda, Daniel D.; Farinella, Paolo; Marzari, Francesco (1996-03-01). "The Formation and Collisional/Dynamical Evolution of the Ida/Dactyl System as Part of the Koronis Family". Icarus. 120 (1): 220–230. doi:10.1006/icar.1996.0047. ISSN 0019-1035.