IAUでの採決始まる

今日の午後9時から採決の模様。さてどうなるか。
ちなみに、決議案の内容は以下の通りです。日本語訳は国立天文台のページ（http://www.nao.ac.jp/nao_topics/data/000232.html）を参考にして下さい。

IAU Resolution: Definition of a Planet in the Solar System

Contemporary observations are changing our understanding of planetary systems, and it is important that our nomenclature for objects reflect our current understanding. This applies, in particlar, to the designation 'planets'. The word 'planet' originally described 'wonderers' that were known only as moving lights in the sky. Recent discoveries lead us to create a new definition, which we can make using currently avaiable scientific information.

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 celestrial 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 and (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".

1 The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
2 An IAU process will be established to assign borderline objects into either dwarf-planet and other categories.
3 These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.

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 celestrial body...

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

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 objcts.

RESOLUTION 6B

The following sentence is added to Resolution 6A:
This category is to be called "plutonian objects."