Deimos

Mars II

Deimos [DEE-mos] (panic) is a moon of Mars and was named after an attendant of the Roman war god Mars. Deimos is a dark body appearing to be composed of C-type surface materials. It is similar to the C-type (blackish carbonaceous chondrite) asteroids that are formed in the outer asteroid belt. It is speculated that Phobos, also a moon of Mars, and Deimos are captured asteroids; however, there are also arguments that go against this theory. Both Phobos and Deimos are saturated with craters. Deimos has a smoother appearance caused by partial filling of some of its craters.

Deimos Statistics

Discovered by .................................... Asaph Hall
Date of discovery ...................................... 1877

Mass (kg) ........................................... 1.8e+15
Mass (Earth = 1) ................................. 3.0120e-10
Radius (km) ..................................... 7.5x6.1x5.5
Radius (Earth = 1) ............................... 1.1759e-03
Mean density (gm/cm^3) .................................. 1.7

Mean distance from Mars (km) ......................... 23,460
Rotational period (days) ............................ 1.26244
Orbital period (days) ............................... 1.26244
Mean orbital velocity (km/sec) ......................... 1.36

Orbital eccentricity ................................... 0.00
Orbital inclination ................................. 0.9-2.7°

Escape Velocity (km/sec) ............................. 0.0057

Visual geometric albedo ................................ 0.07
Magnitude (Vo) ........................................ 12.40

Views of Deimos

Mosaic of Deimos (GIF, 181K)
Measuring 16 by 12 km (10 by 7.5 mi) Deimos circles Mars every 30 hours. Craters of varying age dot its surface, which is somewhat smoother than the surface of Phobos. (Courtesy NASA/JPL).

Deimos (GIF, 13K)
This image was taken by the Viking Orbiter spacecraft in 1977. (NSSDC/NASA).

Deimos (GIF, 50K; JPG, 8K)
This image shows a slightly different view of Deimos. It was acquired by the Viking Orbiter spacecraft. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory/NSSDC/NASA).

Map of Deimos (GIF, 102K; caption)
This image is a photomosaic of Deimos, the outer satellite of Mars. The leading side faces forwards in the orbit of Deimos. The trailing side faces backwards along the orbit. Longitude 0 is at the blunter end with the most prominent craters, and faces Mars. As with all conformal (true shape) projections, the scale in these maps varies, increasing from the centre to the outer edge. (Courtesy Phil Stooke/NSSDC/NASA).

Mars Phobos

Copyright © 1995 by Calvin J. Hamilton. All rights reserved.
Last Modified: June 27, 1995