Hydra (moon)
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Hydra, formal designation Pluto III, is a natural satellite of Pluto, with a diameter of approximately 51 km across its longest dimension. It is the second-largest moon of Pluto, being slightly larger
Discovery images of Nix and Hydra
Hubble image of Pluto's moons (annotated)
Pure Ice Hydra Charon Spectra composite
Nix (moon)
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Nix, formal designation Pluto II, is a natural satellite of Pluto, with a diameter of 49.8 km across its longest dimension. It was discovered along with Pluto's outermost moon Hydra on 15 May 2005 by
Hydra (moon)
…Pluto, with a diameter of approximately 51 km (32 mi) across its longest dimension. It is the second-largest moon of Pluto, being slightly larger than Nix. Hydra was discovered along with Nix by astronomers using the Hubble Space Telescope on 15 May 2005, and was named after the Hydra, the nine-headed…
Enhanced color image of Nix, taken by New Horizons
Nix half illuminated, imaged by New Horizons