Kerberos (moon)

Kerberos (formerly known as S/2011 (134340) 1 and informally as P4) is a small moon of the dwarf planet Pluto. The satellite was discovered on 28 June 2011. It is the fourth moon of Pluto to be discovered. The others are Charon, discovered in 1978, Nix and Hydra, which were discovered in 2005, and Styx, discovered in 2012.

Discovery
The moon was discovered by a Hubble Space Telescope observing team led by Mark Showalter, while they were trying to find out if Pluto had any rings. Kerberos was first seen in a photo taken with Hubble's Wide Field Camera 3, on June 28, 2011. More photos were taken on July 3 and July 18, 2011, to confirm that it exists. The moon was officially verified and announced on July 20, 2011. Kerberos was not seen in earlier Hubble photos because the exposure times were shorter. The moon may have appeared as a very faint smudge in photos taken in 2006, but was ignored because it was not clear. Kerberos is possibly also visible in images taken in 2010. The New Horizons space probe took pictures of Kerberos and Pluto's other moons in 2015.

Structure
Originally, scientists estimated that Kerberos had a diameter of . Later, scientists found out that Kerberos is not round, and has two "lobes", or large round parts. The bigger lobe is about  across, and the smaller one is about  across. Because of its shape, scientists think that Kerberos could have been created when two smaller objects combined together. Because of how the surface of Kerberos reflects light, scientists believe that the surface of Kerberos is covered in water ice.

Kerberos and Pluto's other moons are thought to have been created by a cosmic collision between the dwarf planet and another celestial body early in the Solar System's history.

References

Category:Pluto's moons