Pluto’s three moons

Pluto’s three moons

Fig. 15.4 . Pluto is the brightest object in this image, centered in the diffraction cross. Its large, nearby moon Charon is seen just below and to the right of Pluto. The other two moons, Nix and Hydra, which appear as small points of light to the right of Charon, are about 5,000 times fainter than Pluto. The oversized moon Charon was discovered in 1978, while Nix and Hydra were discovered in mid-2005. Compared to Pluto and its large moon Charon, at 2,360 and 1,210 kilometers in diameter respectively, Nix (inner moon) and Hydra (outer moon) are estimated to be only 40 and 160 kilometers across. They are about two to three times farther from Pluto than Charon is. (Courtesy of NASA/ESA/Harold Weaver, JHUAPL, Alan Stern, SwRI, and the HST Pluto Companion Search Team.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University