Pluto moons get mythical new names
The recently discovered fourth and fifth moons of Pluto now have official names: Kerberos and Styx.
The International Astronomical Union (IAU), charged with official name designations, stipulates that names derive from Greek or Roman mythology.
The names - referring to a three-headed dog and a river separating the living from the dead, ranked second and third in an international public vote.
The winning submission, Vulcan, was vetoed by the IAU.
From planet to dwarf - Pluto's history
- Pluto was a planet for 76 years until it was reclassified as a dwarf planet in 2006
- Pluto's existence was first predicted by Percival Lowell in 1915 and was discovered by Clyde Tombaugh in 1930
- Pluto is now thought to be an object in the Kuiper Belt, a disc-shaped area of icy, dark objects beyond Neptune
Both were spotted by a team using the Hubble space telescope, led by Mark Showalter, senior scientist at the Seti Institute.
The team was initially on a hunt for rings around the dwarf planet - it lost its status as a full planet in 2006.
The ensuing hunt for further planets and objects around it was supported in part by the New Horizons mission, which launched in 2006 on a course toward Pluto and the Kuiper belt of objects beyond it.
It had been suggested that cosmic debris around the dwarf planet may pose a threat to the probe.
Shortly after the first new moon was found, another followed, and the IAU was in the market for two appropriate new names - and the Pluto Rocks! online vote was begun - receiving over half a million votes.
"I was overwhelmed by the public response to the naming campaign," Dr Showalter said.
Vulcan was a suggestion made by William Shatner of the television show Star Trek - the name of the home planet of character Mr Spock.
Although it was a clear winner among the votes, the IAU opted not to use it, on the grounds that it has been used elsewhere in astronomy and not sufficiently associated in mythology with Pluto, the ruler of the underworld.