In sci.astro Wayne L wrote:
Dear Double-A et al:

I submit that the elitist card carrying members of the French IAU who
claim to have discovered these 200 extra solar "planets" have actually so
far discovered exactly zero extra-solar planets.

Hello, there, Wayne, and while I agree with the likely purport of your
statement that IAU Resolution 5A might receive some refinement and
revision, I would emphasize that the IAU is an international organization
in which astronomers from many nations, including the USA, participate.

Also, I recognize that some humor may be intended, but will try to
answer some of your points since they can lead to a better understanding
of the issues.

I also submit that the closest know planets to Pollux are Neptune or Pluto,
depending on the time and/or the French IAU's planet definition for this
week.

An interesting question, which has come up in other threads, is how the
current Resolution 5A should be read in terms of extrasolar planets. One
position I've seen suggested is that an earlier IAU document regarding
extrasolar planets (2001 or so? -- actually, last revision, 2003) might
still apply.

Thus see:

http://www.dtm.ciw.edu/boss/definition.html

For a list of candidate extrasolar planets, interestingly dated
28 August 2006, or four days after the adoption of Resolution 5A,
see:

http://www.dtm.ciw.edu/boss/planets.html

Why?

Because

1. The French IAU is the Supreme and only governing body
of the Universe vested with the power to determine what is and is not a
planet of planetary systems.

Actually I'd say that they're merely establishing some official definitions,
however perfectly or otherwise, for use on Planet Earth -- and that we're
free to propose other usages, or revisions of the current IAU definitions.
Again, I'm not sure how France plays a special role in this -- more below.

2. The French IAU has decreed from on high that there
are only 8 planets in the Universe (see Resolution 5A note 1 below).

I agree that Resolution 5A could have been written better and could use some
revision (the next IAU General Assembly meets in Rio in 2009). However,
much of the wording was borrowed from the work of astronomers in the U.S.A.,
for example the "has cleared the neighbourhood around its orbit" test for
what could have and should have been more expressly defined as a _major_
"planet."

Again, the earlier definition of extrasolar planets and the pages for I
give URL's above suggest that indeed there may be more than eight planets --
"major planets," that is -- in the universe at large.

3. None of these alleged extra-solar star wobble causing
masses are claimed to be orbiting the Sun (see Resolution 5A(1)(a), plus
note 1 below).

Try, of course, and George Dishman and I have been having a lively debate
on just whether and how Resolution 5A might effect extrasolar planets.
I tend myself to assume that the earlier document expressly on these
planets might still more or less hold.


4. There has been no claim or data put forth that these
alleged extra-solar star wobble causing masses have sufficient mass for
their self-gravity to overcome rigid body forces so that they assume a
hydrostatic equilibrium (nearly round) shape, partly or wholly because the
IAU has no definition of what is "sufficient mass" (see Resolution 5A(1)(b)
below.

Well, depending on composition, it might be around 800 km diameter for a planet
like Ceres (which evidently meets the test at around 960 km) -- and a planet
with a mass of 3 jupiters, sustained by degenerate electron pressure, is
rather clearly going to meet it also.

5. No peer review data, nor even "bragging rights" news
releases have been forthcoming showing that these alleged extra-solar star
wobble causing masses have cleared the neighbourhood around their orbits,
mostly because they have no data, and partly because the IAU has provided no
definition of the words "cleared", nor "neighbourhood", as used in
Resolution 5A(1)(c).

However, papers by astronomers such as Stern and Levison (2002), Basri and
Brown (2006), and Soter -- most if not all located in the USA, if I'm right --
have given the concept of "neighborhood clearing" a fairly well-understood
meaning, so that it has become a "term of art," to use a legal phrase.

I'd suspect that while this is a "circumstantial" test -- it depends on the
location of the planet as well as absolute mass -- a superplanet with a
mass of 3 jupiters is likely to meet it over a wide range of cases.

6. The claimed masses of these alleged extra-solar star
wobble causing masses is based on an unproved assumption that the
gravitational constant is the same at their locations as it is on Earth.
Einstein made no such claim.

At times, as I understand, observations can indicate a _minimum_ mass only,
so that sometimes one needs to ask, "Is this actually a planet, or possibly
a brown dwarf at 13 or more jupiters?" More time might be required to refine
one's sense of the orbit, and thus the mass.

Isn't the gravitational constant assumed to follow the Cosmological Principle
that certain natural laws apply uniformly in different parts of the universe?
Cosmologists, is this still a reasonable assumption?

Further, I submit that these 200 extra-solar "planets" are not even dwarf
planets

Because
1. The French IAU is the Supreme and only governing body
of the Universe vested with the power to determine what is and is not a
dwarf planet of planetary systems.

2. None of these alleged extra-solar star wobble causing
masses are claimed to be orbiting the Sun (see Resolution 5A(2)(a)).

What I might suspect is that the extrasolar planet definitions might be the
relevant ones, because any such planet likely to be detected is going to
have enough mass for self-gravity to constrain it to a spheroid shape
reflecting hydrostatic equilibrium.

3. There has been no claim or data put forth that these
alleged extra-solar star wobble causing masses have sufficient mass for
their self-gravity to overcome rigid body forces so that they assume a
hydrostatic equilibrium (nearly round) shape, partly or wholly because the
IAU has no definition of what is "sufficient mass" (see Resolution 5A(2)(b)
below.

See above -- 3 jupiters should be more than sufficient (an interesting
exercise -- by how many orders of magnitude?).


4. No peer review data, nor even "bragging rights" news
releases have been forthcoming showing that these alleged extra-solar star
wobble causing masses have not cleared the neighbourhood around their
orbits, mostly because they have no data, and partly because the IAU has
provided no definition of the words "cleared", nor "neighbourhood", as used
in Resolution 5A(2)(c).

Actually, I'd say that 3 jupiters would likely make it a major planet rather
than a dwarf planet -- Soter sees the concept as applicable to extrasolar
planets, and discusses some possible questions that might arise.


5. The claimed masses of these alleged extra-solar star
wobble causing masses is based on an unproved assumption that the
gravitational constant is the same at their locations as it is on Earth.
Einstein made no such claim.

6. The IAU has yet to provide a process for determining
if borderline objects are either dwarf planets or "other" objects (see
Resolution 5A note 2 below).

Again, this would only apply to objects of a mass _much_ smaller than
three jupiters.

Further, I submit that theses alleged extra-solar star wobble causing
masses are in fact Small Solar-System Bodies (sub category TNOs or "other
small bodies), by the process of elimination and Resolution 5A Section (3)
and note 3, as proclaimed by the Universally Esteemed IAU.


Since they aren't part of our Solar System, the scope of Resolution 5A,
I'd say that some other classification would apply.

Why does the IAU spell neighborhood neighbourhood?

A. They're French

B. They have diminished language skills

C. They can't come to grips with the fact that English is the Universal
language

Actually, "neighbourhood" is a standard British spelling, the Queen's
orthography, as it were. From this viewpoint, my own usage, "neighbhorhood,"
might be taken as a kind of provincialism.

Again, this is not to say that IAU Resolution 5A is flawless -- only that
it reflects the position of a significant group of astronomers, not least
those of the U.S.A. (e.g. Brown and Soter).

Your comments do point to one revision I strongly advocate: making it clear
that the category "planet" in fact means "major planet," with the other two
categories also defining types of planets ("dwarf planets" and Small Solar
System Bodies also known as the smaller "minor planets" -- with comets, in
a persuasive current view, also included as "minor planets").

Also, yes, we could use a definition applying to all planets, solar or
extrasolar.