NASA, ESA, CSA, STScI; J. DePasquale, A. Koekemoer, A. Pagan (STScI) (CC BY 4.0)
A tiny, dusty moon, only about 12 km across, whose origin is still a mystery.
Deimos is only about 12 km across, with a smooth surface covered in fine dust. It orbits Mars in about 30 hours.
Like Phobos, it may be a captured asteroid or may have formed from debris after an impact on Mars; its origin is still debated.
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