GetWiki

{{short description|Smallest and outer moon of Mars}}{{Redirect|Mars II}}{{Use dmy dates|date=April 2020}}

factoids

The Century Dictionary and Cyclopedia (1914) to {{IPAc-en>ˈiːəˈeɪɒURL-STATUS=DEAD TITLE=DEIMOS LEXICO UK ENGLISH DICTIONARY >PUBLISHER=OXFORD UNIVERSITY PRESS, ˈaɪin}}Harry Shipman (2013) Humans in Space: 21st Century Frontiers, p. 317Deimos (deity)>Δεῖμος| discoverer = Asaph Hall| discovered = 12 August 1877Julian day>JD 2456191.5)23455.5|u=km}}23470.9|u=km}}23463.2PUBLISHER=NASA ACCESS-DATE=4 DECEMBER 2013, (6.92 Mars radii)0.00033}}1.263Hour>h)1.3513|u=km/s}}| inclination = 0.93° (to Mars's equator)1.791° (to the local Laplace plane)27.58° (to the ecliptic)| satellite_of = Mars16.0811.7810.22}} km({{valxx|0.10}} km)6.27u=km}}522u=km2}}1033u=km3}}1.51u=kg}}{{refn|Jacobson (2010), as cited in Ernst et al. (2023).}}1.465u=g/cm3}}0.003micro->μg)5.556|ul=m/s}}(20 km/h)Synchronous rotation>Synchronous0.068|0.007}}kelvin>K}}Deimos {{IPAc-en|ˈ|d|aɪ|m|É™|s}} (systematic designation: Mars II) is the smaller and outer of the two natural satellites of Mars, the other being Phobos. Deimos has a mean radius of {{convert|6.2|km|mi|abbr=on}} and takes 30.3 hours to orbit Mars. Deimos is {{convert|23,460|km|mi|abbr=on}} from Mars, much farther than Mars's other moon, Phobos.WEB, Staff, Deimos,weblink 2016, SeaSky.org, 23 January 2016, It is named after Deimos, the Ancient Greek god and personification of dread and terror.

Discovery and Etymology

(File:HallPortrait.jpg|left|thumb|upright|Asaph Hall III, discoverer of Deimos)Deimos was discovered by Asaph Hall at the United States Naval Observatory in Washington, D.C., on 12 August 1877, at about 07:48 UTC.{{efn|Given in contemporary sources as "11 August 14:40" Washington Mean Time, using a pre-1925 astronomical convention of beginning a day at noon,