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Upgrading a moon

Pluto’s satellite meets definitions of plutoid and dwarf planet

6:25pm, August 14, 2008
LAUREL, MD. — Pluto got the boot from planethood in 2006. But one of the dwarf planet’s moons, Charon, could get an upgrade, thanks to discussions August 14 during the Great Planet Debate Conference in Laurel, Md.

“Charon is not a satellite,” Keith Noll, a planetary scientist at the Space Telescope Science Institute in Baltimore, said during the meeting. “It meets the definitions of plutoid and dwarf planet, and if it weren’t orbiting Pluto, it would be a dwarf planet.”

But when the International Astronomical Union redefined planet and created the label dwarf planet, the group listed Charon as one of Pluto’s satellites — Nix and Hydra being the other two. In 2006, the IAU also wrote, “The idea that Charon might qualify to be called a dwarf planet on its own may be considered later,” as a footnote to their definitions of planet and dwarf planet.

Stirring even more controv

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