Pluto's status is on the chopping block

The general feeling was the Americans were blocking reclassification purely on nationalistic grounds - Pluto was discovered after all by an American who was a mentor to a lot of American planetary scientists. This current proposal is a classic fudge - let's see how it works, at least it keeps our American friends happy :lol:

why am I not surpriosed.

Wouldn't you love to be a fly on the wall in that discussion!

well, you can actually!
www.astronomy2006.com/

It appears that the term "plutons" if off the table for now.
There was a debate at the conference today re planets/pluto. Watching it at the mo.

Clear skies,

Current proposal to define a planet as of today is:

RESOLUTION 5 (draft)
The IAU therefore resolves that planets and other bodies in planetary systems be defined in the following way:

1) A planet is a celestrial body that (a) has sufficient mass for it's self-gravity to overcome rigid forces so that it assumes a hydrostatic equilibrium (nearly round) shape 1 , and (b) is in orbit around a star, and is neither a star or a brown dwarf.

2) In our Solar System, we distinguish between the eight "classical planets" as the dominant objects in their local population zones, and "dwarf planets" which are not.

3) All natural non-planet objects orbiting the Sun, currently including the Solar System asteroids, near-Earth objects (NEOs), Mars- Neptune- Jupiter- trojan asteroids, most Centaurs, most Trans-Neptunian Objects (TNOs), and comets, shall be referred to collectively as "Small Solar System Bodies". In the new nomencalture, the terms "minor planet" is not used.

1 - This generally applies to objects with mass above 5 x 10^20 kg and diameter greater than 800km. An IAU process will be established to examine planet canditates near this boundary.

May the debate begin!

RESOLUTION 6 (Draft)

The IAU further resolves:
Pluto is a dwarf planet by the above definition, as are one or more recently discovered large trans-Neptunian objects. In contrast to the classical planets, these objects have orbital periods in excess of 200 years and typically have highly inclined with large eccentricities. We designate this category of planetary objects, of which Pluto is a prototype, as a new class that we call "XXXXX". We propose that the MPC create a new and separate catalog for these objects and their orbital characteristics, with Pluto as the first entry.

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Where "XXXXX" =
plutons, plutoids, plutonids, plutonoids, plutinos (already used), Tombaugh Objects, Tombaugh Planets or plutians

RESOLUTION 7 (Draft)

The IAU further resolves:
For two or more objects comprising a multiple object system, the primary object is designated a planet if it independently satisfies the definition of a planet. A secondary object satisfying these conditions is also designated a planet if over most of the orbital period the system's centre of gravity resides outside the primary. Secondary objects not satisfying these criteria are satellites.

Well, lots of controversy in Prague apparently and it appears that a further draft has been developed along the lines of:

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 the dominant object in its local population zone, and (c) is in orbit around the Sun.

This is to keep it limited to our Solar System as the one quoted previously referred to "planetary systems", which could suggest that it applies to extra-solar planets also.

Apparently, the way it's looking this evening is that it'll either be accepted in what will probably be a further slightly revised form, or it will be deferred for another three years. However, nobody expressed an interest in keeping Pluto as a planet and Resolutions 6 and 7 had a majority support from the straw poll of the antendees.

So, it would appear that's Pluto's days as a planet as at an end.