Fifth moon around Pluto

Fifth moon around Pluto

Credit: NASA This image, taken by NASA's Hubble Space Telescope, shows five moons orbiting the distant, icy dwarf planet Pluto. The green circle marks the newly discovered moon, designated P5, as photographed by Hubble's Wide Field Camera 3 on July 7. The observations will help scientists in their planning for the July 2015 flyby of Pluto by NASA's New Horizons spacecraft. P4 was uncovered in Hubble imagery in 2011.

LOS ANGELES -- There's something lurking around distant and icy dwarf planet Pluto: a fifth moon.

A team of scientists using the Hubble Space Telescope said Wednesday they have discovered the tiniest moon yet around Pluto. That brings the number of known moons to five.

The mini-moon is estimated to be up to 15 miles (24 kilometers) across, smaller than the one that scientists spotted last year, which is up to 21 miles (34 kilometers) wide. Pluto's largest moon, Charon, is about 650 miles (1,000 kilometers) across.

Until the newly found moon gets a name, it will be known as P5.

A NASA spacecraft named New Horizons will arrive at Pluto in 2015. When New Horizons launched in 2006, Pluto was a full-fledged planet, but astronomers have since demoted it to dwarf planet.