[X] My Assistant

[SFJCody]

http://groups.yahoo.com/group/mpml/message/15111

[alan]

Brown's webpage has an update on progress on deciding whether 2003 UB313 is a planet or not

The above gives my personal view on how to resolve the planetary status. The official decision will come from the International Astronomical Union. We had hoped for a timely decision but we instead appear to be stuck in committee limbo. Here is the story, as best I can reconstruct it from the hints and rumors that I hear:

    *  A special committee of the International Astronomical Union (IAU) was charged with determining "what is a planet."
    * Sometime around the end of 2005, this committee voted by a narrow margin for the "pluto and everything bigger" definition, or something close to it.
    *  The exectutive committee of the IAU then decided to ask the Division of Planetary Sciences (DPS) of the American Astronomical Society to make a reccomendation.
    * The DPS asked their committee to look in to it.
    * The DPS committee decided to form a special committee.
    * Rumor has emerged that when the IAU general assembly meets in August in Prauge they willl make a decision on how to make a final decision!

So when do we expect a decision? Back in August 2005 I used to joke that the IAU was so slow they might take until 2006 before deciding. That was supposed to be a joke. Now I joke that I hope there is a decision by the time my daughter starts grade school and learns about planets in class. She is currently 7 months old.

[SFJCody]

http://www.newscientistspace.com/article.ns?id=dn8681

[David]

http://www.newscientistspace.com/article.ns?id=dn8681

You know, planets were being defined and undefined and given names long before the IAU existed. If the IAU insists on sitting on its hands for years and years, I think that astronomers and astronomy-buffs ought to take matters into their own hands and simply adopt a solution. I suspect that the IAU committee have just been thinking too hard about the question. I recommend a solution that required almost no thinking at all :

My solution is:
Our solar system has ten planets; they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto and Proserpina.

The minimal amount of thought that went into it was this:

Pluto has been accepted as a planet for 76 years and that is unlikely to change regardless of what the IAU thinks;
If Pluto is a planet, there is no reason for 2003 UB313 not to be a planet, since it goes around the sun and is bigger than Pluto;
Therefore 2003 UB313 will be accepted as a planet.

I use the name Proserpina, because even though it wouldn't be my first choice for the name, discoverer Mike Brown has favored either Persephone or Proserpina, and Latin forms are preferred for planets.

Edit: I should add that the only way that this represents my private view is that I want to see the nonsense cut through and a decision finally arrived at. I think that this is likely to be what happens at the end of the argument anyway, and I'd rather have it happen immediately than in two, three, or five years' time. I'd be just as happy with a decision that a body has to be at least as big (or as massive) as Mercury in order to be a planet.

[ljk4-1]

You know, planets were being defined and undefined and given names long before the IAU existed.  If the IAU insists on sitting on its hands for years and years, I think that astronomers and astronomy-buffs ought to take matters into their own hands and simply adopt a solution.  I suspect that the IAU committee have just been thinking too hard about the question.  I recommend a solution that required almost no thinking at all    :

My solution is:
Our solar system has ten planets; they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto and Proserpina.

The minimal amount of thought that went into it was this:

Pluto has been accepted as a planet for 76 years and that is unlikely to change regardless of what the IAU thinks;
If Pluto is a planet, there is no reason for 2003 UB313 not to be a planet, since it goes around the sun and is bigger than Pluto;
Therefore 2003 UB313 will be accepted as a planet.

I use the name Proserpina, because even though it wouldn't be my first choice for the name, discoverer Mike Brown has favored either Persephone or Proserpina, and Latin forms are preferred for planets.

Plus you can now say "My Very Educated Mother Just Served Us Nine Pizzas Politely" or Punctually or Pleasantly.

But what happens when we find other KBOs bigger than Pluto and Proserpina, as I am sure we will? Better start using other mythologies besides the Greek:

http://www.pantheon.org/

[ljk4-1]

Astrophysics, abstract
astro-ph/0602316

From: David E. Trilling [view email]

Date: Tue, 14 Feb 2006 19:52:04 GMT (484kb)

The Albedo, Size, and Density of Binary Kuiper Belt Object (47171) 1999 TC36

Authors: J.A. Stansberry, W.M. Grundy, J.L. Margot, D.P. Cruikshank, J. P. Emery, G.H. Rieke, D.E. Trilling

Comments: ApJ, in press (May, 2006)

We measured the system-integrated thermal emission of the binary Kuiper Belt Object 1999 TC36 at wavelengths near 24 and 70 microns using the Spitzer space telescope. We fit these data and the visual magnitude using both the Standard Thermal Model and thermophysical models. We find that the effective diameter of the binary is 405 km, with a range of 350 -- 470 km, and the effective visible geometric albedo for the system is 0.079 with a range of 0.055 -- 0.11. The binary orbit, magnitude contrast between the components, and system mass have been determined from HST data (Margot et al., 2004; 2005a; 2005b). Our effective diameter, combined with that system mass, indicate an average density for the objects of 0.5 g/cm3, with a range 0.3 -- 0.8 g/cm3. This density is low compared to that of materials expected to be abundant in solid bodies in the trans-Neptunian region, requiring 50 -- 75% of the interior of 1999 TC36 be taken up by void space. This conclusion is not greatly affected if 1999 TC36 is ``differentiated'' (in the sense of having either a rocky or just a non-porous core). If the primary is itself a binary, the average density of that (hypothetical) triple system would be in the range 0.4 -- 1.1 g/cm3, with a porosity in the range 15 -- 70%.

http://arxiv.org/abs/astro-ph/0602316