The Debate Over Planethood

Last year, on August 1, I wrote:

If we do consider Pluto a planet, then 2003UB313 must also be certified as a planet and given a name that is easier to remember. My fear is that astronomers will continue to find large objects in the Kuiper belt that argue for planet status. Before long, we will have dozens of planets in the solar system, and third grade science will suddenly become much more difficult.

Today the AP reports:

Much-maligned Pluto would remain a planet -- and its largest moon plus two other heavenly bodies would join Earth's neighborhood -- under a draft resolution to be formally presented Wednesday to the International Astronomical Union (IAU), the arbiter of what is and is not a planet. . . .

Besides reaffirming the status of puny Pluto -- whose detractors insist should not be a planet at all -- the new lineup would include 2003 UB313, the farthest-known object in the solar system and nicknamed Xena; Pluto's largest moon, Charon; and the asteroid Ceres, which was a planet in the 1800s before it was demoted.

According to Wikipedia (which I trust more than I should), Pluto, "Xena," Charon, and Ceres would be considered "dwarf planets," setting them apart from the eight classical planets (My Very Earnest Mother, etc.). Pluto and Charon specifically would be classified as a "double planet." The IAU has named eight other candidates for "dwarf planet" status, all of which are also classified as plutons, or planetary objects with elliptical orbits that orbit beyond Neptune.

I applaud this move. Pluto and "Xena" should both be considered planets, but they certainly aren't planets in the same sense that Mercury-through-Neptune are planets. I am most excited by the inclusion of Ceres, located in the asteroid belt between Mars and Jupiter; but I'm not comfortable with Ceres being grouped with Pluto, Charon, and "Xena." Because of Ceres' circular orbit and proximity to the sun, it should be classified as either an asteroid or a planet proper.