Deimos (moon)

Deimos
Deimos-MRO.jpg
An enhanced-color image of Deimos ( MRO, 21 February 2009).
Image: NASA/JPL-Caltech/University of Arizona
Discovery
Discovered by Asaph Hall
Discovery date 12 August 1877
Designations
Adjectives Deimosian
Orbital characteristics
Epoch 2012-Sep-21
( JD 2456191.5)
Periapsis 23455.5 km
Apoapsis 23470.9 km
23463.2 km [1] (6.92 Mars radii)
Eccentricity 0.00033 [1]
1.263  d [1]
(30.312 h)
1.3513 km/s [2]
Inclination 0.93° (to Mars's equator)
1.791° (to the local Laplace plane) [1]
27.58° (to the ecliptic)
Satellite of Mars
Physical characteristics
Dimensions 15 × 12.2 × 11 km [3]
Mean radius
6.2 ± 0.18 km [4]
(0.97316 mEarths)
495.1548 km2
(97.0755 µEarths)
Volume 999.78 km3
(92.2979 nEarths)
Mass 1.4762×1015 kg [2]
(0.247179 nEarths)
Mean density
1.471±0.166 g/cm3 [4]
0.003 m/s2 [2]
(306 µ g)
5.556 m/s
(20 km/h) [2]
Synchronous [1]
Albedo 0.068 ± 0.007 [4]
Temperature ≈ 233 K
12.89 [5]

Deimos ( systematic designation: Mars II) [6] is the smaller and outer of the two natural satellites of the planet Mars, the other being Phobos. Deimos has a mean radius of 6.2 km (3.9 mi) [1] and takes 30.3 hours [1] to orbit Mars. In Greek mythology, Deimos is the twin brother of Phobos and personified terror.

Deimos is 23,460 km (14,580 mi) from Mars, much farther than Mars's other moon, Phobos. [7]

Discovery

Deimos ( Viking 2, 5 October 1977) [8]

Deimos was discovered by Asaph Hall, III at the United States Naval Observatory in Washington, D.C on 12 August 1877, at about 07:48 UTC (given in contemporary sources as "11 August 14:40" Washington Mean Time, using an astronomical convention of beginning a day at noon, so 12 hours must be added to get the actual local mean time). [9] [10] [11] [12] Hall also discovered Phobos on 18 August 1877, at about 09:14 GMT, after deliberately searching for Martian moons.

It is named after Deimos, a figure representing dread in Greek mythology. [6] The names, at first spelled Phobus and Deimus, were suggested by Henry Madan (1838–1901), [6] Science Master of Eton, from Book XV of the Iliad, where Ares (the Roman god Mars) summons Dread ( Deimos) and Fear ( Phobos). [13]

Other Languages
Afrikaans: Deimos (maan)
العربية: ديموس
Avañe'ẽ: Deimos
azərbaycanca: Deymos
Bân-lâm-gú: Deimos (oē-chheⁿ)
беларуская: Дэймас
беларуская (тарашкевіца)‎: Дэймас
български: Деймос (спътник)
brezhoneg: Deimos (loarenn)
čeština: Deimos (měsíc)
corsu: Deimos
Deutsch: Deimos (Mond)
eesti: Deimos
emiliàn e rumagnòl: Deimos
Esperanto: Dejmo (luno)
français: Déimos (lune)
Gaeilge: Deimos
Gàidhlig: Deimos
Հայերեն: Դեյմոս
हिन्दी: डेमोस
hrvatski: Deimos (mjesec)
Ido: Deimos
Bahasa Indonesia: Deimos (satelit)
interlingua: Deimos (luna)
íslenska: Deimos
ქართული: დეიმოსი
коми: Деймос
Кыргызча: Деймос
Lëtzebuergesch: Deimos (Mound)
македонски: Дејмос
मराठी: डीमॉस
Mìng-dĕ̤ng-ngṳ̄: Deimos (ôi-sĭng)
Nederlands: Deimos (maan)
norsk: Deimos
norsk nynorsk: Marsmånen Deimos
Plattdüütsch: Deimos (Maand)
português: Deimos (satélite)
rumantsch: Deimos (glina)
русский: Деймос
shqip: Deimosi
Simple English: Deimos (moon)
slovenčina: Deimos (mesiac)
slovenščina: Deimos (luna)
ślůnski: Deimos
српски / srpski: Дејмос
srpskohrvatski / српскохрватски: Deimos (mjesec)
suomi: Deimos
ไทย: ดีมอส
Türkçe: Deimos (uydu)
українська: Деймос (супутник)
Tiếng Việt: Deimos (vệ tinh)
粵語: 火衞二
Zeêuws: Deimos (maen)
中文: 火卫二