Kerberos (moon)

Pluto P4

Kerberos is a small moon of Pluto, discovered in 2011 by the Hubble Space Telescope team led by Mark R. Showalter. Its discovery was part of a program to search for potential hazards to the New Horizons spacecraft, which flew by Pluto in July 2015. Kerberos orbits Pluto at a distance of approximately 58,000 kilometers (36,000 miles), positioning it between the orbits of Nix and Hydra, two other small moons of Pluto. Before its official naming, Kerberos was known by the provisional designation S/2011 (134340) 1.

Discovery and Naming

Kerberos was discovered through observations made with the Hubble Space Telescope's Wide Field Camera 3 in late June 2011. The discovery team used a technique called astronomical imaging to reveal the moon's presence, a method that involves taking multiple images of the same area of space to identify moving objects. Kerberos was officially named after the three-headed dog of Greek mythology that guards the entrance to the underworld, a theme consistent with the naming of Pluto and its other moons, which also draw from underworld mythology. The name was adopted by the International Astronomical Union (IAU) in 2013.

Physical Characteristics

Kerberos is one of Pluto's smaller moons, with an estimated diameter of 19 kilometers (12 miles) for its larger lobe and 9 kilometers (5.6 miles) for its smaller lobe, suggesting a highly elongated shape. This shape, along with its brightness, indicates that Kerberos could be a binary object that merged into a single body, a common occurrence in the Kuiper Belt. Its surface is likely composed of water ice, similar to Pluto's other moons. The moon's brightness is lower than expected, which was a surprise to astronomers and suggests a surface covered in dark material.

Orbit and Rotation

Kerberos orbits Pluto in a nearly circular orbit and is in a 5:1 mean-motion resonance with Charon, Pluto's largest moon. This resonance means that for every orbit Charon completes, Kerberos completes roughly one-fifth of its orbit. The dynamics of Pluto's moons, including Kerberos, are complex due to their interactions with Charon, which acts as a massive perturber in the system.

Exploration

Kerberos, along with Pluto's other moons, was observed by the New Horizons spacecraft during its flyby in 2015. These observations provided valuable data on its size, shape, and orbit, contributing to our understanding of the Pluto system. However, due to its small size and the limitations of the spacecraft's instruments, detailed information about Kerberos's surface composition and geology remains limited.

Significance

The discovery and subsequent observations of Kerberos have important implications for our understanding of the Kuiper Belt and the processes that govern the formation and evolution of planetary systems. Studying Kerberos and Pluto's other moons helps astronomers understand the diversity of objects in the outer solar system and the mechanisms by which they form and evolve.