[meteorite-list] And the winner is-- Plutoid!

[lebofsky at lpl.arizona.edu]

Hi All:

I will probably be going to the August meeting in Maryland, so it will be
interesting to see how this new terminology goes over.

So everything round and icy (maybe) is a Plutoid, which means Pluto-like.
Since we don't know what Pluto is (at least what to define it as), this
really makes a whole lot of sense. NOT!

I predict it will go over like a lead balloon.

Larry L.

The previous statements are the opinion of the author and may not reflect
the opinions of other scientists.



On Wed, June 11, 2008 12:58 pm, Darren Garrison wrote:

> http://www.space.com/scienceastronomy/080611-plutoid-planets.html

>

>

> Pluto Now Called a Plutoid

> By Robert Roy Britt

> Senior Science Writer

> posted: 11 June 2008

> 10:30 am ET

>

>

> Updated 2:00 p.m. ET

>

>

> Pluto's years-long identity crisis just got more complex today.

>

>

> The International Astronomical Union has decided on the term "plutoid" as

> a name for Pluto and other objects that just two years ago were redefined

> as "dwarf planets."

>

> The surprise decision is unlikely to stem ongoing controversy and

> confusion, astronomers say.

>

> Sidestepping concerns of many astronomers worldwide, the IAU's decision,

> at a meeting of its Executive Committee in Oslo, comes almost two years

> after it stripped Pluto of its planethood and introduced the term "dwarf

> planets" for Pluto and other small round objects that often travel highly

> elliptical paths around the sun in the far reaches of the solar system.

>

> "Most of the people in astronomy and planetary science community had no

> idea this was going to come out," said Hal Weaver of the Johns Hopkins

> University

> Applied Physics Laboratory. Weaver called the new definition "sort of

> outdated, outmoded, archaic."

>

> A meeting in August at the Applied Physics Laboratory is slated to debate

> the entire topic of defining planets. Meanwhile, other astronomers said

> the new definition needed more definition or that it might simply not be

> used.

>

> "This seems like an unattractive term and an unnecessary one to me," said

> David

> Morrison, an astronomer at NASA's Ames Research Center who, in 2006, said

> the IAU's actions on Pluto have created major rifts among astronomers.

>

>

> The new definition

>

>

> The name plutoid was proposed by the members of the IAU Committee on

> Small Body

> Nomenclature (CSBN), accepted by the Board of Division III and by the IAU

> Working Group for Planetary System Nomenclature (WGPSN), and approved by

> the IAU Executive Committee at its recent meeting in Oslo, according to a

> statement released today.

>

> Here's the official new definition:

>

>

> "Plutoids are celestial bodies in orbit around the sun at a distance

> greater than that of Neptune that have sufficient mass for their

> self-gravity to overcome rigid body forces so that they assume a

> hydrostatic equilibrium (near-spherical) shape, and that have not cleared

> the neighborhood around their orbit."

>

> In short: small round things beyond Neptune that orbit the sun and have

> lots of rocky neighbors.

>

> The two known and named plutoids are Pluto and Eris, the IAU stated. The

> organization expects more plutoids will be found.

>

> "Rather than resistance to 'plutoid,' I think we'll just be hearing

> groans," said Stephen J. Kortenkamp, senior scientist at the Planetary

> Science Institute

> in Tucson.

>

> Controversy continues

>

>

> One IAU leader recognizes it is adding to an ongoing controversy.

>

>

> The IAU has been responsible for naming planetary bodies and their

> satellites since the early 1900s. Its decision in 2006 to demote Pluto was

> highly controversial, with some astronomers saying simply that they would

> not heed it and questioning the IAU's validity as a governing body.

>

> "The IAU is a democratic organization, thus open to comments and

> criticism of any kind," IAU General Secretary Karel A. van der Hucht told

> SPACE.com by email

> today. "Given the history of the issue, we will probably never reach a

> complete consensus."

>

> Van der Hucht said the new designation is not a further demotion for the

> once-favorite planet of grade-school children: "Pluto is now the prototype

> of a very interesting category of outer solar system bodies."

>

> IAU Division III President Edward L.G. Bowell of the Lowell Observatory

> said the ruling stems from unfinished business from the forging of a

> planet definition in 2006. Bowell said there is no agreed-upon way to

> define "dwarf planet" yet, so "officers of the IAU thought it would be a

> good idea to adopt alternative criteria that would at least allow those

> large bodies to be named as though they were dwarf planets."

>

> It remains to be seen whether astronomers will use the new term.

>

>

> "My guess is that no one is going to much use this term, though perhaps

> I'm

> wrong," said Caltech astronomer Mike Brown, who has led the discovery of

> several objects in the outer solar system, including Eris. "But I don't

> think that this will be because it is controversial, just not particularly

> necessary."

>

> Brown was unaware of the new definition until the IAU announced it today.

>

>

> "Back when the term 'pluton' was nixed they said they would come up with

> another one," Brown said. "So I guess they finally did."

>

> Reactions were not all negative, however.

>

>

> "It seems like a reasonable decision to me, and given the excitement

> generated by New Horizons [a NASA probe headed for Pluto], it's in

> everyone's interest to favor the largest Kuiper belt objects with their

> own categorical designation," said Gregory Laughlin, a University of

> California, Santa Cruz extrasolar planet

> researcher.

>

> "The only fly in the ointment that I can envision is if a plutoid larger,

> than, say, Mars is detected," Laughlin points out. "In that case, I think

> we'd see a big flare-up of the what-is-a-planet debate."

>

> More debate coming

>

>

> The dwarf planet Ceres (which used to be called an asteroid, and before

> that was called a planet!) is not a plutoid as it is located in the

> asteroid belt between Mars and Jupiter, according to the IAU. Current

> scientific knowledge lends credence to the belief that Ceres is the only

> object of its kind, the IAU stated. Therefore, a separate category of

> Ceres-like dwarf planets will not be

> proposed at this time, the reasoning goes.

>

> Weaver, the Johns Hopkins researcher, has helped organized a meeting,

> planned earlier this year for Aug. 14-16 at Johns Hopkins University

> Applied Physics

> Laboratory, that aims to bring astronomers of varying viewpoints together

> to discuss the controversy.

>

> "We're not trying to slam the IAU, it's just that we also don't want to

> lead people to the idea that there's a handful of people who decide where

> science should go," Weaver said today. The meeting is designed to "address

> this question in terms of a scientific conference." He said no votes will

> be taken at the meeting. Rather, it's a time to "sit back and take stock

> of everything we've learned in the past couple of decades."

>

> The term plutoid joins a host of other odd words -- plutinos, centaurs,

> cubewanos and EKOs -- that astronomers have conjured in recent years to

> define objects in the outer solar system, whose appearance seems to grow

> more complex every year.

>

> Kortenkamp wonders if "plutoid" isn't just one more confusing term in the

> cosmic lexicon.

>

> "So Pluto is a Kuiper belt object, a plutino (the unofficial but nearly

> universally accepted name for objects in the 2:3 resonance with Neptune),

> a dwarf planet, and now also a plutoid?" he said. "If the IAU is trying to

> make things more clear, I think it needs to try again. This is just

> another layer of confusion that will feed the "pluto is a planet" camp at

> the [Johns Hopkings] meeting."

>

> Kortenkamp also thinks the new defiinition leaves Ceres up in the air:

> "And this

> "-oid" classification doesn't apply to Ceres?" he asks. "Okay, so does

> that means we continue calling Ceres an ASTERoid?"

>

> Asked if Ceres remains a dwarf planet and is not an asteroid, Bowell, the

> IAU

> official, said: "I think so!"

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