English: This image, taken by NASA's Hubble Space Telescope, shows five moons orbiting the distant, icy dwarf planet Pluto. The newly discovered small moon, Styx (initially designated P5), is the innermost of the moons found by Hubble over the past seven years. The diagram shows that Styx is in a 58,000-mile-diameter circular orbit around Pluto that is assumed to be co-planar with the other satellites in the system. Though Charon (discovered in 1978) is an even closer moon to Pluto, some astronomers consider the Pluto-Charon pair a "double planet" because Charon's mass is 12 percent of Pluto's mass (by comparison, our Moon is 1.2 percent Earth's mass). This image was taken with Hubble's Wide Field Camera 3 on July 7. Other observations that collectively show the moon's orbital motion were taken on June 26, 27, and 29, 2012 and July 9, 2012. The new data will help scientists in their planning for the July 2015 flyby of Pluto by NASA's New Horizons spacecraft.

The original NASA image has been modified by replacing "P4" and "P5" with newer designations "Kerberos" and "Styx", respectively.