Pluto’s Moons Get Names

P4 and P5 Get Their Official Names

In modern times, the honor of suggesting names for celestial objects is rightfully reserved for the person or persons who discover them. They send their list of names to the International Astronomical Union, which has the job of certifying the suggested names. A committee at the IAU checks to make sure the names aren’t already taken, that they fit whatever naming scheme may be in place for the category of objects, and then if everything checks out, they approve the names. The actual discoverers can use whatever means they like to come up with names. Some objects, such as Venus, have naming schemes that dictate the types of names that can be chosen. In Venus’s case, features are named after prominent women, goddess names, etc.  Other objects, such as exoplanets, don’t have naming schemes beyond the current practice of using the name of the star and alphabet letters to designate a given planet. The Uwingu group has been busily compiling lists of popularly chosen names for exoplanet discoverers to use if they like.

Popular naming came into play when two new moons were discovered orbiting the dwarf planet Pluto. They were quickly designated P4 and P5, and the team that discovered had the privilege of suggesting permanent names. The team, led by astronomer Mark Showalter, a senior research scientist at the SETI Institute, decided to have the Institute run a public naming contest called Pluto Rocks. People could send in whatever names they felt were appropriate, and the contest then forwarded the most popular names for consideration to the IAU.

Yesterday the SETI Institute announced that the IAU had formally approved the  names Kerberos for P4 and Styx, for P5. These fit well with the mythological status of Pluto as the guardian of the underworld. In Greek mythology, Kerberos is a three-headed dog who guards the entrance to Hades (the underworld), while Styx is the river that separates Hades from the world of the living.

Pluto is gaining increasing attention as the New Horizons spacecraft gets closer to its 2015 goal of exploring this intriguing system that lies in the far reaches of the solar system. Certainly Pluto’s moons will come under intense scrutiny, and the spacecraft could discover more moons too small to see even with Hubble’s sharp eye.