Ok… Let’s try this again shall we?
It’s official! There are eight planets in our solar system. The vote has taken place. Last week’s proposals have been rejected. Pluto has been demoted, apparently.
They were voting on the following (I got this here):
1) A planet1 is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
(2) A dwarf planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape2, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
(3) All other objects3 orbiting the Sun shall be referred to collectively as “Small Solar System Bodies”.
1The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
2An IAU process will be established to assign borderline objects into either dwarf planet and other categories.
3These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.
That was resolution 5A, and then there is 5B:
Insert the word “classical” before the word “planet” in Resolution 5A, Section (1), and footnote 1. Thus reading:
(1) A classical planet1 is a celestial body . . .
And then the Pluto-specific resolutions (actually, 5B seems to lay the groundwork of the attempt to save Pluto):
The IAU further resolves:
Pluto is a dwarf planet by the above definition and is recognized as the prototype of a new category of trans-Neptunian objects.
The following sentence is added to Resolution 6A:
This category is to be called “plutonian objects.”
Anyway, from what I heard, looks like these attempts to keep it have been rejected – those last few resolutions were voted down – and Pluto has been given the chop.
[Update: BBC story on it here.]