Main Page | See live article | Alphabetical index Deimos Discovery Discovered by Asaph Hall Discovered in 1877 Orbital characteristics Mean radius 23,459 km Eccentricity 0.00033 Revolution period 1d 6h 17.9m Inclination 1.79° Is a satellite of Mars Physical characteristics Equatorial diameter 15(×12.2×11) km Surface area km2 Mass 1.8×1015 kg Mean density 1.7 g/cm3 Surface gravity m/s2 Rotation period 1d 6h 17.9m Axial tilt ° Albedo 0.07 Surface temp min mean max K K K Atmospheric pressure 0 kPa Deimos ("DEE mos") is the smaller and outermost of Mars' two moonss. It is the smallest known moon in the solar system, though smaller undiscovered ones undoubtedly exist around the outer planets. It was discovered on August 10 1877 by Asaph Hall. Deimos is composed of carbon-rich rock, much like C-type (carbonaceous chondrite) asteroids, and ice. It is heavily cratered. It is probably an asteroid that was perturbed by Jupiter into an orbit that allowed it to be captured by Mars, though this theory is still in some dispute. Like most bodies of its size, Deimos is highly nonspherical with dimensions of 15×12.2×11 km. An image of Deimos taken by the Viking 1 orbiter. See Also: List of features on Phobos and Deimos\n This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.