Deimos

In Greek mythology, Deimos is one of the sons of Ares (Mars) and Aphrodite (Venus); "deimos" is Greek for "panic".

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Deimos ("DEE mos") is the smaller and outermost of Mars' two moons. It is the smallest known moon in the solar system. 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.

http://meta.wikipedia.com/upload/deimos-viking1-thumb.jpg

An image of Deimos taken by the Viking 1 orbiter. click here for full-sized image

• Orbital radius: 23,459 km
• Diameter: 12.6 km (15 x 12.2 x 11)
• Mass: 1.8×10¹⁵ kg
• Density: 1.7 g/cm³
• Orbital period: 1.26244 days
• Orbital inclination: 0.9-2.7°