Redefining Planets

I have been hearing about this redefinition process going on with the IAU and the basic definition of planet sounds good to me.

“A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet.”

Not that I get a vote on it. But, I would suggest one additional qualification. That the celestial body have a mean radius greater than 2000 km. Eventually, gravity will let all aggregates form into spherical shapes. For a planet, size matters as well.

For those bodies that have a mean radius of 500-2000 km, let them be called plutons, or minor planets, or something similar.

Let bodies with a mean radius of less than 500 km be asteroids or space junk or dark matter. Things to blow up as you are escaping the Empire’s Star Cruisers.