It's now, officially, a "plutonian object"

[matgb]

BBC reports that the resolution is passed.

RESOLUTION 5A

The IAU therefore resolves that planets and other bodies in our Solar System be defined into three distinct categories in the following way:

(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".

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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.

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RESOLUTION 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

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¹The eight classical planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

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IAU Resolution: Pluto

RESOLUTION 6A
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.

RESOLUTION 6B

The following sentence is added to Resolution 6A:

This category is to be called "plutonian objects."

You'd have thought that, during their biggest conference news in years, they'd manage to not schedule essential maintenence on their main website? Mirrors are fine, but the mirroe is way down the Google results for them.

ETA: They rejected resolution 5B, which means that a dwarf planet is not a type of planet, but a wholly different thing. So they've both redefined the solar system and the rules of grammar. Go IAU!

Comments

[bokuniwa.livejournal.com]

Thank heavens. I was rooting for this sort of outcome.

[matgb]

Aye, planetoids, dwarf planets, plutonian objects, whatever.

Having 300+ planets would have been daft. OTOH, having a twin planet and a planet in the asteroid belt wouldn've been interesting...

[dainul.livejournal.com]

I'm just entertained by the level of ranting this has incurred. Seems that everyone and his mother has taken up arms, almost literally for one side or the other. Would be nice if they could come up with a decision that, when used literally, didn't exclude most of the 'classical' planets, too, though.

[matgb]

It is funny isn't it. Completely irrelevent to anything, but it's got people talking.

Just confirmed with our grammar specialist in teaching, you can't call something a "dwarf planet" without it actually being a planet sub-type, so theyy're either re-writing grammar or can't add up.