Yeah, when trying to classify bodies in a continuum population, arbitrary distinctions are really unavoidable. In a way, that's kind of the root of the problem: we're now dealing with a continuum population (as far as size is concerned at least) whereas that wasn't the case before.

Before Charon's discovery, the distinction between planet and asteroid was pretty clear. From Mercury to Earth was a 19-fold difference in mass; from Earth to Neptune a 17-fold difference; and from Neptune to Jupiter an 18-fold difference. But from Ceres to Mercury is a 380-fold difference which provided a nice dividing line.

With Charon's discovery, Pluto's mass became known and it dropped neatly into the middle of that nice neat 380-fold difference, being 15 times as massive as Ceres but 25 times less massive than Mercury. The new object UB313 might end up being almost right at the logarithmic "half-way" point. No more neat distinction.

In a way, I can understand the IAU's reluctance to make a decision now. It might really be better for them to just keep stalling. There really isn't any rush -- Pluto and UB313 will still be there in ten years, by which time we will probably have a much better grasp of the size distribution of the bodies in the Kuiper Belt and inner Oort Cloud. At the rate that large KBO's are being discovered these days, there should be a lot more of them known in a few years. Making the decision now will almost guarantee having to either retract it, or heavily modify it, sometime down the road. For the rest of us, it's a frustrating wait, but it might cause less confusion in the long run.

Maybe 2015, New Horizons' arrival at Pluto, would be a good target date for deciding whether Pluto ought to be called a planet. Same goes for UB313 and any other similar objects found between now and then.

dvandorn said "I guess you could call the "dwarf" varieties something else, like "minor planets" or "planetoids," but I like dwarf better. "

I think they prefer to be called 'diameter-challenged'.

Phil

Volume constrained!

Although there is no mention of any of the three new giant KBOs other than 2003 EL61 (AKA K40506A ) at http://www.aas.org/publications/baas/v37n3...s2005block.html

I have found some information suggesting that new data on 2003 UB313 will be presented on Thursday. Dunno what it'll be though.

Results from the new Spitzer observations?

That or Keck.

Interesting article. What happens to our discussion if they find half dozen Earth sized TNO's in the next few years?

http://www.spacedaily.com/news/kuiper-05e.html

I was looking for one of these charts, Thanks to above post!. It shows 2003 UB313 size in relation to Pluto and the moon.





http://skyandtelescope.com/news/article_1560_1.asp

http://cfa-www.harvard.edu/iauc/RecentIAUCs.html

Fragment from IAUC 8596:

http://www.centauri-dreams.org/2005.08.28_...l#1125582509708

An Infrared Hunt for Artificial Kuiper Belt Objects

If extraterrestrials were to set up a colony in our Solar System, where would they choose to settle? Gregory Matloff and Anthony R. Martin make the case for the Kuiper Belt in a recent paper for the Journal of the British Interplanetary Society. Kuiper Belt Objects (KBOs) are, after all, easy to exploit as a resource base without the burden of a planet's gravity well. They are rich in volatile materials (more so than main belt asteroids), close enough to the Sun to harvest solar power, and far enough out that visits by those of us living in the inner Solar System would be few and far between.

Moreover, the orbits of KBOs are relatively unaffected by planetary perturbations. Matloff was intrigued enough by these factors to make a proposed infrared search of the Kuiper Belt the subject of a 2004 paper ("A Proposed Infrared Search for Artificial Kuiper Belt Objects," JBIS 57, pp. 283-287). His new paper follows this up with an examination of the characteristics that artificial KBOs ought to display, comparing these to known objects.

How big would such an artificial habitat be? The earlier paper assumed a radius of five kilometers, on the same order of magnitude as some O'Neill designs that would house 10,000 people and more, but the authors of this new study factor in size variations up to 50 kilometers and weigh the effects of varying degrees of reflectivity. Certain assumptions are unavoidable: Matloff and Martin assume, for example, that the temperature of an artificial KBO is within the range 273-373 K, the temperature range of liquid water.

The authors find that the K-band astronomical photometric filter is sensitive to radiation temperature variations in their hypothetical artifical KBO (this is a significant result, for Earth's atmosphere is relatively transparent in this spectral band). They also discuss visible bands of infrared in which artificial objects should be distinguishable from real KBOs. The authors then run their criteria against NASA's Planetary Data System. A small number of real objects have characteristics similar to those predicted for artificial bodies.

This work thus results in an initial selection of targets for an advanced infrared search for artificial objects, using these criteria:

Low mass KBOs are favored, making plutinos primary targets (plutinos are small objects locked, as is Pluto, in an orbital resonance with Neptune).
Stable orbits are favored, making classical objects the next target (these are KBOs with circular orbits but often high inclinations (in excess of 30 degrees).
Highly eccentric orbits offer the least likely candidates.

The authors examine the facilities available for infrared observation, from large ground-based telescopes using adaptive optics (think ESO's Very Large Telescope in Chile, or the twin Keck telescopes on Mauna Kea in Hawaii) to the Hubble Space Telescope, the Infrared Space Observatory and the Spitzer Space Telescope. "The intriguing situation exists that only a few real KBOs have photometric characteristics similar to those predicted for artificial bodies, but infrared observations of KBOs are limited," Matloff and Martin write.

Their paper concludes with a series of suggestions for improving such observational data, including studies in the K-band and coordinated use of Hubble and Spitzer to obtain full infrared data on the targeted KBOs. The paper is Gregory L. Matloff and Anthony R. Martin, "Suggested Targets for an Infrared Search for Artificial Kuiper Belt Objects," JBIS 58 (January/February 2005), pp. 51-61.

http://www.newscientist.com/article.ns?id=dn7968

[quote=ljk4-1,Sep 8 2005, 04:21 PM]
http://www.centauri-dreams.org/2005.08.28_...l#1125582509708

An Infrared Hunt for Artificial Kuiper Belt Objects

Fascinating, sounds like something Carl Sagan might have published in Icarus when he was editor. Kinda like SETI but a lot closer. I always thought that advanced propulsion ideas should be studied for traces of their use that could be detected from a distance and those signs searched for, such as Bussard ramjets and nuclear pulse vehicles. It is said that the 'loudest' radio traces fro Earth by far were the above ground nuclear tests. Such radio signitures coming from the tests (or wars) of other civilizations may be long reaching signals worth looking for.

Don

[quote=DDAVIS,Sep 8 2005, 12:09 PM]
[quote=ljk4-1,Sep 8 2005, 04:21 PM]
http://www.centauri-dreams.org/2005.08.28_...l#1125582509708

An Infrared Hunt for Artificial Kuiper Belt Objects

Fascinating, sounds like something Carl Sagan might have published in Icarus when he was editor. Kinda like SETI but a lot closer. I always thought that advanced propulsion ideas should be studied for traces of their use that could be detected from a distance and those signs searched for, such as Bussard ramjets and nuclear pulse vehicles. It is said that the 'loudest' radio traces fro Earth by far were the above ground nuclear tests. Such radio signitures coming from the tests (or wars) of other civilizations may be long reaching signals worth looking for.

Don

[/quote]

According to G. Lemarchand in his 1992 article Detectability of Extraterrestrial Technological Activities:

Elliot estimated the distance at which the United States "Starfish" nuclear test could be detected by our present technology of X-ray detectors. Assuming that the energy of the explosion is equivalent to 1.4 megatons and that the X-ray pulse was equally intense in all directions, he found that this explosion should be detected from a distance of ~400 Astronomical Units, about ten times the radius of Pluto's solar orbit.

Supposing that all the terrestrial nuclear powers [3] pooled their nuclear weapons stockpiles to produce a single explosion in space (E~2x10 to the 4 power megatons). Considering that the X-ray pulse could be concentrated into a conical beam of about thirty degrees in angle with no loss of radiation, a typical terrestrial X-ray detector should be able to detect a signal from a distance of ~190 light years.

3 - In 1989 the United States and the Soviet Union had almost 55,000 nuclear warheads with a combined destructive power of 15,500 megatons (Source: Bulletin of Atomic Scientist, 1990).

The full article here:

http://www.coseti.org/lemarch1.htm

Along with Orion, this could be another "good" use for nuclear weapons.

Here is an article by G. Matloff that is quite similar to the previous one on searching for artificial KBOs.

http://www.nidsci.org/essaycomp/gmatloff.html

Interesting quote:

"If starships have crossed to our solar system within past eons (perhaps accelerated by solar sails and decelerated by a combination of magnetic reflection of interstellar ions and solar sails), they may have created a myriad of artificial worldlets from asteroidal and cometary material. We may live within a "Dyson Sphere" (53) of millions of space habitats, each masquerading as a small comet nucleus or asteroid.

"In the absence of directed radio transmissions from the extraterrestrials to the Earth, detection will be challenging, but not impossible. One method of detection might be a search for excess infrared emissions from asteroidal objects (5)."

Why dont they just eat us and live on Earth??

Earth just isn't suitable for life - apart from the obvious fact that it's gravity is far too high for life to develop, the surface is largely molten, and the high-temperature resistant silicon materials normally found below the H2O rock crust on proper planets are constantly attacked by the free oxygen and even - amazingly - molten rock 'rain' in it's super-dense and ultra-hot atmosphere. Oh, and there's the radiation flux from the sun, and some hints that the planet itself may have extensive radiation belts, too. No, life on Earth is just a foolish fantasy entertained by the ignorant!

Ahh!! I knew that there was a logical explanation.

On a slightly different point I recall that one of the Pioneers or Voyagers was subject to a detectable deflection by a TNO when it was beyond the orbit of Pluto. Can anyone recall any detail about this event or am I just dreaming?

http://sfgate.com/cgi-bin/article.cgi?f=/c...TL&type=science

Work continues on solar system's new objects

http://www.spaceflightnow.com/news/n0509/09solarssytem/

Distant solar system body may be cigar-shaped

http://www.newscientistspace.com/article.ns?id=dn7968

Thanks for the new article.

--- The three objects were all detected with the 48-inch Samuel Oschin Telescope at Palomar Observatory by a team composed of planetary scientists from the California Institute of Technology, the Gemini Observatory, and Yale University. ---

Official identification - Nickname

2003 EL61 - Santa with the moon Rudolph

2005 FY9 - Easterbunny

2003 UB313 - Xena

--- If indeed Xena reflects 70 percent of the sunlight (similar to that of Pluto) reaching it, as does Pluto, then Xena is about 2700 kilometers in diameter. ---

Spitzer data: --- At any rate, the researchers hope that infrared data returned by the Spitzer Space Telescope over the weekend of August 27-28, in addition to recently obtained data from the 30-meter IRAM telescope in Spain, will help nail down Xena's size. ---

http://news.bbc.co.uk/1/hi/sci/tech/4230056.stm

This makes for a good flyby target - you could map the whole thing at high resolution with one NH spacecraft, and it would be interesting to see the effects such a spin would have on the surface.

These statements are just not compatible.

I am not at all sure that I buy this.

I can see at least two alternative explanations. The first possibility is that we are looking at a strong difference in albedo between the two hemispheres, similar to the case of Iapetus. This would also produce the observed light-curve shape, and seems a lot more physically plausible to me.

The second possibility is that we are looking at a very close binary system. The limiting case would be a contact binary with two equal-sized bodies, each one 35% of the mass of Pluto. Given a 3.9 hour orbital period, we would have a center-of-mass to center-of-mass separation of 1450 km, allowing for a radius of each body of up to 725 km. A body with 35% of Pluto's mass and a radius of 725 km would have a density of 2.87 times that of water.

The other limit is the case where all the mass is concentrated in one body with 70% of Pluto's mass and a radius of 1450 km, giving a density of 1.47 times that of water.

At Pluto's density of 2.1 times that of water, a combined mass of 70 % of Pluto, and a center-of-mass to center-of-mass separation of 1450 km, a contact binary would have one body with 63% of Pluto's mass and a radius of 980 km, and the second body having a mass of 7% of Pluto and a radius of 470 km, for a mass ratio of 9 to 1 (compared to the Pluto/Charon system with a mass ratio of 7 to 1). The secondary object would have a radius 48% of its primary, compared to Charon having a radius 52% of Pluto.

Bill

I'm interest precovery bright TNO. Help me add its table.

This abstract http://www.aas.org/publications/baas/v37n3/dps2005/786.htm gives 2003 EL61 mass as 30.2% of Pluto's mass. That gives a center to center separation of 1120 km for a close binary of two equal mass objects. If the bodies had the same density as Pluto they would have diameters of 1280 km. A contact binary might be possible. Once they determine the actual size from the albedo they should be able to better determine its actual shape.

Alan do you know anything about the gravitational deflection one of the Pioneers or Voyagers experienced that may have indicated a distant encounter with a TNO. I seem to remember reading about it some years ago but cant find any reference to it on th net, even Mr. Google is ignorant about it and I am wondering if my memory is failing.

I hope this question doesn't drift in the direction of 'funny physics'...

Is this what you are refering to? (pdf)
http://citebase.eprints.org/cgi-bin/fullte...stro-ph/0503368

PIONEER 10 DEFLECTED BY A KUIPER BELT OBJECT? Preliminary results indicate that Pioneer 10 has had an encounter with a Trans-Neptunian object at 56 AU. Using coherent radio Doppler data generated by the Deep Space Network (DSN) at S band frequencies (wavelength ~ 13 cm), PN 10 experienced a gravitational deflection in December 1992. The new body, found by a team at Queen Mary and Westfield College in London, UK, and the Jet Propulsion Laboratory in California, is probably a so-called Kuiper Belt object. If the observations are confirmed by other astronomers, it will be only the second time in history that a Solar System object has been discovered by its gravitational effect alone. The first was the planet Neptune which was discovered in 1846. Its position was predicted because of its gravitational tug on the planet Uranus, which appeared to be behaving oddly following its discovery 59 years earlier.

This story was reported by BBC News Online Science Editor Dr David Whitehouse on 28 September 1999
http://news.bbc.co.uk/1/hi/sci/tech/460095.stm

Thank you for the effort Alan.

A few quotes from the article above

"On 8 December, 1992, when Pioneer was 8.4 billion km (5.2 billion miles) away, they saw that it had been deflected from its course for about 25 days."
With Pioneer travelling at 15km/s it would indicate a big object would it not?


Has anything come of this, it happened 13 years ago? Was it ever visually observed from Earth?
"In a few weeks time, they are expected to be able to place an upper limit on the mass of the object and make predictions about its position. Early indications suggest it may be an object that is being ejected from our Solar System after encountering a major planet."

How about going to the source? Here is his homepage
http://www.sp.ph.ic.ac.uk/~giacomo/noframes.html

I have despatched an email, will let you know if anything interesting returns.

One Find, Two Astronomers: An Ethical Brawl
http://www.nytimes.com/2005/09/13/science/space/13plan.html

Photometric Observations Constraining the Size, Shape, and Albedo
of 2003 EL61, a Rapidly Rotating, Pluto-Sized Object in the Kuiper
Belt


http://arxiv.org/abs/astro-ph/0509401

Wow, with three numbers: mass, rotation rate, light curve they were able to significantly constrain the dimensions and density. If its rotation is aligned with the orbit of its satellite it would be ~ 2000 km x 1500 km x 1000 km with a density near 2.6 g/cm^3. That would make it mostly rock, our moon's density is ~ 3.3 g/cm^3.

Astronomers reject the term 'planet'

http://www.nature.com/news/2005/050919/full/437456a.html

http://www.space.com/scienceastronomy/0509...definition.html

http://www.timesonline.co.uk/article/0,,11...1791282,00.html
Progress!

Maybe -- but also note in the Space.com article:

""Today, a news article in the journal Nature states that the working group has come up with the adjective-adding solution and may forward the final proposal to the IAU Executive Committee within two weeks.

"If that's to be the case, then the group's chairman, Iwan Williams of Queen Mary, University of London, will likely have to act without consensus. 'Every time we think some of us are reaching a consensus, then somebody says something to show very clearly that we're not,' said Brian Marsden, a member of the group and leader of the Minor Planet Center where newfound objects are catalogued.

"Today Marsden told SPACE.com that it's not clear if a consensus will be reached soon. 'I thought maybe we were close,' he said, 'but just yesterday somebody [in the group] insisted we define planet.' That's the very effort that's gone mostly in circles for many months, however."

_________________________________________

This is bearing more and more of a resemblance to that 30-year debate they had in Laputa over how long to boil a 3-minute egg.

Meanwhile, the fight over credit for the Planet 10 discovery has just gotten substantially nastier:

http://www.newscientistspace.com/article/d...f-web-data.html

Which Yahoo groups mailing list is that?


Bob C.

This is a very unfortunate development. I am concerned that it will actively discourage the sort of publication of earlyt raw data or planning information as part of public outreach efforts that the folks in this forum and amateurs around the world thrive on.

Bruce:

Wasn't it armed rebellion, and wasn't it about whether it was the pointy end or the round end you ate first?

I think it's *good* to see astronomers going in circles - it sure beats them ellipse things hollow!

Perhaps they need 'A Modest Proposal' of their own...

Bob Shaw

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

The discovery of 2003 EL61 is controversial, not the discovery of 2003 UB313. 2003 EL61 is the giant cigar-shaped KBO with a satellite.

Not to nitpick too much, but only the circumstances of the discovery are worth of controversy, not the discovery itself. From what I've just seen in the contents of some of the links in this thread... well, after the 2003 UB313 drama, it seems pretty clear who is going to get the dubious distinction of being a footnote to astronomical history. You just can't expect anyone to take anything you say seriously after such a massive loss of credibility.

This was a really huge mistake for the Spanish group. NOBODY in their field will EVER forget about this. Time to get fitted for that millstone.

I guess they thought that they were going to get to be Urbain Leverrier. But now they're not even going to get to be John Couch Adams.

Phooey on them.

Oops. I'm getting my UBs mixed up... At any rate, this event DID panic Brown into announcing the discovery of Planet 10 earlier than he'd planned, before somebody could pull a similar trick with it.

Like to shar with you an email I received today from Giacomo Giampieri

Thank you for your interest in our research, and sorry for the delay in
answering your query.

The signal we studied in 1999 was very interesting and peculiar.
Unfortunately, a single flyby (assuming that the signal was real) does
not allow an unambiguous measure of the mass and the orbital parameter
of the alleged body. We could determine a rather wide range of possible
values for its position, but given that 7 years were already passed,
the uncertainty in the body's position was too big to allow for an
optical detection. Lacking an independent confirmation of the body
existence, we could not draw any final conclusion about the signal that
we saw.

I hope this answers your query.

Best regards,

Giacomo Giampieri

On 11 Sep 2005, at 04:32, Richard K. wrote:>
> Hi
> I have been reading with interest an old news article
>
> http://news.bbc.co.uk/1/hi/sci/tech/460095.stm
> A few quotes from the article above
>
> “PN 10 experienced a gravitational deflection in December 1992.
> This story was reported by BBC News Online Science Editor Dr David
> Whitehouse on 28 September 1999”
> "On 8 December, 1992, when Pioneer was 8.4 billion km (5.2 billion
> miles) away, they saw that it had been deflected from its course for
> about 25 days."
>
> With Pioneer travelling at 15km/s it would indicate a big object
> would it not?
>
>
> Has anything come of this, it happened 13 years ago? Was it ever
> visually observed from Earth?
>
> "In a few weeks time, they are expected to be able to place an upper
> limit on the mass of the object and make predictions about its
> position. Early indications suggest it may be an object that is being
> ejected from our Solar System after encountering a major planet."
>
> I would very much appreciate any information
>
> Richard K
> Australia

Like to share with you an email I received today from Giacomo Giampieri

Thank you for your interest in our research, and sorry for the delay in
answering your query.

The signal we studied in 1999 was very interesting and peculiar.
Unfortunately, a single flyby (assuming that the signal was real) does
not allow an unambiguous measure of the mass and the orbital parameter
of the alleged body. We could determine a rather wide range of possible
values for its position, but given that 7 years were already passed,
the uncertainty in the body's position was too big to allow for an
optical detection. Lacking an independent confirmation of the body
existence, we could not draw any final conclusion about the signal that
we saw.

I hope this answers your query.

Best regards,

Giacomo Giampieri

On 11 Sep 2005, at 04:32, Richard K. wrote:>
> Hi
> I have been reading with interest an old news article
>
> http://news.bbc.co.uk/1/hi/sci/tech/460095.stm
> A few quotes from the article above
>
> “PN 10 experienced a gravitational deflection in December 1992.
> This story was reported by BBC News Online Science Editor Dr David
> Whitehouse on 28 September 1999”
> "On 8 December, 1992, when Pioneer was 8.4 billion km (5.2 billion
> miles) away, they saw that it had been deflected from its course for
> about 25 days."
>
> With Pioneer travelling at 15km/s it would indicate a big object
> would it not?
>
>
> Has anything come of this, it happened 13 years ago? Was it ever
> visually observed from Earth?
>
>
> I would very much appreciate any information
>
> Richard K
> Australia

HST observed 2003 UB313 on December 3 as part of a TNO satellite survey.

http://www.stsci.edu/cgi-bin/get-visit-status?10545

...and will do so again before the end of the week, in an attempt to measure the object's size.

http://www.stsci.edu/cgi-bin/get-proposal-info?10759

No news on IAU decision.

I notice it is with the ACS HRC. I wonder if it will be able to see surface detail (It will depend on whether or not it has large scale albedo variations).