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Unmanned Spaceflight.com _ Pluto / KBO _ "Aernus"

Posted by: ustrax Oct 11 2007, 08:40 AM

Tomorrow at DPS Patryk Lykawka will make a presentation where he points out to the existence of a planet with the diameter of the Earth at 100AU.

I received his answers regarding the work done yesterday, here's some of it (the rest is you know http://spaceurope.blogspot.com/...):

"This massive planetesimal would be, now, at this moment in the history of the Solar System, orbiting the Sun at a distance of, at least, 100 AU, or, simplifying, 3 to 4 times more distant from our star than Pluto.
A far, massive, transplutonian planet in the Lykawka’s description who remarks the importance that the orbital evolution of this planet may be the key to answer several unexplained enigmas of the Kuiper Belt, among which he points out a few…:
The excitation actually observed in the region between 40 and 50 AU is one, another are the populations of different types of objects in the Belt and their orbital characteristics.
Another two pieces of the puzzle can also be put into place under Patrik work: the Belt’s truncated region in the 48 AU region and its small total mass."

What's your opinion regarding this?...
According to him this is not like Planet X, his study even erases Planet X from the map...

EDITED: "Aernus" is the name I'm using, it was the divinity of the Zoelae, a pre-historic tribe that lived in the most remote corner of my country...

Posted by: ngunn Oct 11 2007, 09:14 AM

Interesting. A massive distant planet is one way to account for the orbit of Sedna. I don't know if one Earth mass is enough though.

Posted by: ustrax Oct 11 2007, 09:20 AM

QUOTE (ngunn @ Oct 11 2007, 10:14 AM) *
Interesting. A massive distant planet is one way to account for the orbit of Sedna. I don't know if one Earth mass is enough though.


The same diameter but tenths of Earth mass if I understood correctly... wink.gif

Posted by: nprev Oct 11 2007, 09:36 AM

<sigh>. I knew this would happen...time to contact the SIRTF folks & try to get some allocated observation time. Gonna be tough, even if the damn thing's really there.

Just to clarify: I personally expect that there's at least one Mars-sized body or better in loose orbit around the Sun out to a half light-year or so. I wouldn't be surprised if there are more than that, nor would discovery of a gas-giant-class object at far greater distances be beyond the pale.

In addition to dynamical effects on the Kuiper Belt, the presence or absence of such objects might tell us a great deal about the history of the Solar System, at least from the viewpoint of how often or recently the Sun has passed near other stars. Hell, come to that, something out there might well be a capture, particularly if it's in an eccentric orbit...

Posted by: ustrax Oct 11 2007, 11:09 AM

QUOTE (nprev @ Oct 11 2007, 10:36 AM) *
Just to clarify: I personally expect that there's at least one Mars-sized body or better in loose orbit around the Sun out to a half light-year or so. I wouldn't be surprised if there are more than that, nor would discovery of a gas-giant-class object at far greater distances be beyond the pale.


Sounds plausible to me, but I am really curious to know how will be reactions to the presentation...

Time for a Kuyper Belt grand tour mission...
What a crop of planets that would be! wink.gif

Posted by: belleraphon1 Oct 11 2007, 01:08 PM

ustrax and all...

regarding Aernus' composition......

according to the following reference work...

"MASS-RADIUS RELATIONSHIPS FOR SOLID EXOPLANETS
S. Seager, M. Kuchner, C. A. Hier-Majumder, B. Militzer4
http://fr.arxiv.org/PS_cache/arxiv/pdf/0707/0707.2895v1.pdf

Using the graph on page 21, "Mass-radius relationship for solid planets" it is indeed theorectically possible to have a one Earth radius planet but just .3 Earth mass if the composition is rocky with a lot of ices.

Very Cool!!!!!

Craig

Posted by: ustrax Oct 11 2007, 01:32 PM

QUOTE (belleraphon1 @ Oct 11 2007, 02:08 PM) *
Very Cool!!!!!


Very cool is also http://harbor.scitec.kobe-u.ac.jp/~patryk/index-en.html, I've heard some and like a few, e.g. "Mankind Roots"... cool.gif

Posted by: alan Oct 11 2007, 04:26 PM

QUOTE (ustrax @ Oct 11 2007, 03:40 AM) *
Tomorrow at DPS Patryk Lykawka will make a presentation where he points out to the existence of a planet with the diameter of the Earth at 100AU....

...Another two pieces of the puzzle can also be put into place under Patrik work: the Belt’s truncated region in the 48 AU region and its small total mass."

does this mean it has cleared its neighborhood?

ducks and runs

Posted by: Alan Stern Oct 11 2007, 04:39 PM

QUOTE (ustrax @ Oct 11 2007, 11:09 AM) *
Sounds plausible to me, but I am really curious to know how will be reactions to the presentation...

Time for a Kuyper Belt grand tour mission...
What a crop of planets that would be! wink.gif



Of course, none are planets, even Earth-sized-- says the IAU. Good thing they have no police force, since so few are following their "law".

Posted by: David Oct 11 2007, 08:26 PM

QUOTE (Alan Stern @ Oct 11 2007, 04:39 PM) *
Of course, none are planets, even Earth-sized-- says the IAU. Good thing they have no police force, since so few are following their "law".


Your job title: Planetary Police Officer
Your employer: The International Astronomical Union
Your task: Scour the fringes of the Solar System, and break up excessively large planets before they can pose a threat to astronomical law and order.

The fate of the planetary regulatory regime depends on you!

Applicants for this position are welcome from any planet. Plutonians need not apply.

Posted by: tuvas Oct 12 2007, 01:36 PM

QUOTE (alan @ Oct 11 2007, 09:26 AM) *
does this mean it has cleared its neighborhood?

ducks and runs


I would guess that yes, although Sedna might be a problem... Hmmm... Still, it would take a long time to prove it...

Posted by: Greg Hullender Oct 12 2007, 04:46 PM

So was the presentation given? Is it available online now? Was it well-received?

If "Aernus" fails to qualify as a planet, I'm afraid the likeliest reason won't be failure to clear its orbit -- it'll be failure to be in orbit in the first place. I'll be particularly interested to see if the paper gives a clear suggestion as to where to look for this thing.

--Greg

Posted by: ustrax Oct 12 2007, 04:57 PM

QUOTE (Greg Hullender @ Oct 12 2007, 05:46 PM) *
So was the presentation given? Is it available online now? Was it well-received?


I can't answer you that but I'm waiting for Lykawka contact regarding the post-presentation...
Maybe during the weekend as he must be returning to Japan, but Emily told me she had someone covering it...let's wait...

Now the sun shines, it is friday...I'll go surf for an hour or two...Good weekend to you all! wink.gif

Posted by: ustrax Oct 13 2007, 01:45 PM

Here's a http://spaceurope.blogspot.com/2007/10/u-p-d-t-e-as-in-previous-post-i-made.html, Lykawka sounded a bit sad for the short minutes he had to present his work...maybe from here on things will improve... wink.gif

Posted by: nprev Oct 14 2007, 02:11 AM

Damn...those are by far the tightest time constraints I've ever seen for a presentation!!! blink.gif

Actually, though, that's a good thing...seen too many meetings descend into chaos because of open time limits (some people, usually in the audience, apparently think that they are paid by the word...) This method keeps the focus tight, tends to minimize grand-standing and B.S.

Best of all, this idea is resonating in the heads of the attendees, some of whom will pursue the concept independently and contact Lykawka for productive one-on-one discussion. I don't think he should feel sad at all; it sounds like a resounding success! smile.gif

Posted by: tuvas Oct 14 2007, 02:55 PM

QUOTE (ngunn @ Oct 11 2007, 02:14 AM) *
Interesting. A massive distant planet is one way to account for the orbit of Sedna. I don't know if one Earth mass is enough though.


If one earth mass wasn't enough, maybe they are in some kind of a resonance. That would allow for a difference in orbit gradually over time. That might even help to find such an object...

Posted by: ustrax Oct 15 2007, 10:06 AM

I've asked David Tholen (the responsible for the latest Pluto system images) about this, if he had knowledge of it, I didn't publish this in the blog because it was a bit off topic, but there's one thing he said that made me scratch my head more vigourously...
He told me that he was aware of predictions for a much larger object being even farther out... rolleyes.gif

Posted by: ngunn Oct 15 2007, 11:57 AM

QUOTE (ustrax @ Oct 15 2007, 11:06 AM) *
He told me that he was aware of predictions for a much larger object being even farther out... rolleyes.gif


What? - Just one? cool.gif

Posted by: SigurRosFan Dec 14 2007, 11:12 AM

Here's the arXiv preprint:

- http://arxiv.org/abs/0712.2198

Posted by: ngunn Dec 14 2007, 11:22 AM

Thanks very much for that - duly printed off for holiday reading.

Posted by: ustrax Jan 7 2008, 09:20 AM

Patryk Lykawka provided the link for downloading the http://harbor.scitec.kobe-u.ac.jp/~patryk/Patryk-Planetoid.pdf (8.84MB) directly from his site.

Posted by: marsbug Jan 7 2008, 05:03 PM

Thanks ustrax that'll make for fascinating lunch break reading!

Posted by: alan Jan 21 2008, 04:52 AM

New Scientist has an article discussing Lykawka's theory in the Jan 12 issue.
http://space.newscientist.com/article/mg19726381.600-the-mystery-of-planet-x.html

Levison and Morbidelli have there own paper to explain the properties of the Kuiper belt.
http://arxiv.org/abs/0712.0553

Posted by: Greg Hullender Jun 18 2008, 07:12 PM

MSNBC is running a story on this today:

http://harbor.scitec.kobe-u.ac.jp/~patryk/Lykawka-Planetoid.pdf

Apparently Patryk has a new paper in the Astrophysical Journal today, although I can't find a link to it on his site:

http://harbor.scitec.kobe-u.ac.jp/~patryk/index-en.html

My biggest question, though, is why he thinks it would only be a "plutoid," since he seems to be describing a very large (Earth-diameter, but 1/3 mass) object well outside the Kuiper Belt -- something that almost certainly would have cleared its orbit.

--Greg

Posted by: nprev Jun 18 2008, 09:59 PM

I think he's erring on the side of caution and using the largest category of currently recognized trans-Neptunian objects by the IAU; seems sensible to me.

If you think the Pluto debate has been a debacle, just wait 20 years or so when I personally think we'll find a couple of dozen Mars-sized or better objects out there to struggle with. I'm gonna go with Stephen's nomenclature on another thread and start using "thingys".

Posted by: Alan Stern Jun 18 2008, 11:03 PM

QUOTE (Greg Hullender @ Jun 18 2008, 07:12 PM) *
MSNBC is running a story on this today:

http://harbor.scitec.kobe-u.ac.jp/~patryk/Lykawka-Planetoid.pdf

Apparently Patryk has a new paper in the Astrophysical Journal today, although I can't find a link to it on his site:

http://harbor.scitec.kobe-u.ac.jp/~patryk/index-en.html

My biggest question, though, is why he thinks it would only be a "plutoid," since he seems to be describing a very large (Earth-diameter, but 1/3 mass) object well outside the Kuiper Belt -- something that almost certainly would have cleared its orbit.

--Greg


At Pluto's orbit, Earth would not be a planet by IAU standards. Silly, I know. At 100 AU, a several Earth mass object would be disqualified. This is a consequence of the zone clearing criteria which biases what is and is not a planet by distance-- so that objects that are planets at 1 AU like Earth are not planets at 30 AU. You know what I think of this. Now for a prediction: It shall fall before NH reaches Pluto. Too many people are figuring it out. Google "Great Planet Debate."

-Alan

Posted by: ElkGroveDan Jun 18 2008, 11:52 PM

Organizations such as IAU exist by virtue of broad agreement to accept their declarations and rulings. When these groups tread outside the bounds of popular opinion and become controversial they risk that universal acceptance and accordingly their usefulness as an organization comes into question. Not that I'm part of any cabal, or anything like that.

Posted by: nprev Jun 19 2008, 12:31 AM

(Sigh)...yeah, and it's a damn shame that it happened, too. Up till this point, the IAU has been one of the least controversial and most respected organizations there is. Unfortunately, I think it was inevitable as well, and there will be other emerging issues in the near future as well (for example, let's all try to obtain a precise definition of a brown dwarf once we've got a broad sample of their population; ain't gonna be pretty.)

Classification in an absolute human-subjective sense does not lend itself well to almost any feature or aspect of the actual Universe. Reality stretches our self-imposed boundaries, always. Just watch: we're gonna find things like 'galaxies' in intergalactic space with fewer stars than an open cluster. The naming of names will never be over.

For the far future, wait till when and if we ever discover a complex alien ecosystem; the words 'animal' and 'plant' will become instantly obsolete. Hell, they already are in a lot of ways.

Sorry to belabor the point. I just don't ever see a neat solution to the problem, and it goes far beyond astronomy.


Posted by: JRehling Jun 19 2008, 12:34 AM

Even beyond the controversy, we've had the following categories invoked re: Pluto's possible membership in the past several years:

Planet (pre-2006 status)
Planet (the definition it had for a few days including Ceres, Eris, and Charon)
Planet (the latest definition, excluding Pluto)
Minor Planet (re: proposals to give it a Minor Planet number)
Dwarf Planet
Kuiper Belt Object
Trans-Neptunian Object
Plutino
Plutoid
Planetoid?

Pluto is in six to eight of these categories by the current official reckoning, which is remarkable when you consider that we don't know that much about it. This is a mess. It was honestly someone's idea to look at the previously existing nine categories and conjure up a new one?

How many times can you screw up a joke before the audience wants you off the stage? The IAU is *way* past that limit.

Posted by: tasp Jun 19 2008, 01:29 AM

My apologies if someone else has thought of this first and I didn't notice (or if it is impossible . . . )

IIRC, quite a few objects out Pluto way seem to be resonant with Neptune. (3:2 springs to mind)

Are any other solar orbital periods suspiciously common amongst the remainder of the other objects ??

Or any commensurabilities??


Like if we are seeing several objects with periods around (just picking a random #) 313 years and another bunch at 469 years, it seems like something "might be up".

Maybe something large out at 626 years, or 939 years?

(I realize checking all the ratios is annoying and involves something called 'math' . . . . )




Posted by: Greg Hullender Jun 19 2008, 01:48 AM

QUOTE (Alan Stern @ Jun 18 2008, 04:03 PM) *
At 100 AU, a several Earth mass object would be disqualified. This is a consequence of the zone clearing criteria which biases what is and is not a planet by distance


But the Kuiper Belt ends at 55 AU, right? Why wouldn't an Earth-sized object at 100 AU be a planet, provided it orbited in splendid isolation?

QUOTE (Alan Stern @ Jun 18 2008, 04:03 PM) *
Now for a prediction: It shall fall before NH reaches Pluto.


I wouldn't be surprised if results from Pan-STARRS and/or LSST will force a radical rethink, and I note first light for LSST is scheduled for about the same time as N reaches Pluto.

But the real reason I posted here was to see a) if anyone has a link to the actual paper and cool.gif how serious one ought to take it.

--Greg

Posted by: JRehling Jun 19 2008, 04:27 AM

QUOTE (Greg Hullender @ Jun 18 2008, 06:48 PM) *
But the Kuiper Belt ends at 55 AU, right? Why wouldn't an Earth-sized object at 100 AU be a planet, provided it orbited in splendid isolation?


I guess the thought would be that that can't happen. For an Earth-sized object to be at 100 AU, the stuff for it to accrete out of has to be out there at about 100 AU. It couldn't have formed somewhere else and then made its way out there and just stopped unless there were something bigger out there. (A highly felicitous impact that significantly changed its orbit could do so, providing it didn't blast enough stuff off to once again reject the axiom.)

The period of an object at 100 AU is 1000 years. The volume of space around its orbit proportional to that of Earth is a million times as great. I'm certain the Earth hadn't cleared its orbit in 4.5 million years (the impacts on the Moon make that clear -- not by a long shot). So there's no reason to suspect that the "Early Heavy Bombardment" would even be over at that distance. Unless there wasn't enough stuff there for an Earth-sized object to accrete.

Posted by: Greg Hullender Jun 19 2008, 02:55 PM

QUOTE (JRehling @ Jun 18 2008, 09:27 PM) *
I guess the thought would be that that can't happen.


If that's the case, that's fine; I'm surprised we'd be that confident, though. Seems to depend a lot on assumptions about the original mass of the disk out there, plus the original composition. We can't already know everything or we wouldn't need to send NH out there! ;-)

Getting back to the paper (or the news article about the paper), it appears he's claiming this object is large enough to establish the outer edge of the Kuiper Belt -- just as Jupiter establishes (I think) the outer edge of the Asteroid Belt. Unless you take a rather disingenuous interpretation of "clearing the orbit" ("I want this orbit clean enough to EAT off of!") :-) then I'd say that anything that can limit the Kuiper Belt has really gone above and beyond the call of duty as far as orbit-cleaning goes.

Which gets back to my original question (which wasn't aimed at continuing the "is it a planet discussion"): Is Lykawka's hypothesis reasonable?

--Greg

Posted by: JRehling Jun 19 2008, 03:16 PM

QUOTE (Greg Hullender @ Jun 19 2008, 07:55 AM) *
If that's the case, that's fine; I'm surprised we'd be that confident, though. Seems to depend a lot on assumptions about the original mass of the disk out there, plus the original composition. We can't already know everything or we wouldn't need to send NH out there! ;-)


Actually, my [non-professional] assessment doesn't depend on any assumptions about the original conditions. It handles all of them. Either there never was any stuff out there, or there was and it can't have ALL been consolidated into one body in so short a time. Even if the long orbital periods are the only difference between Earth and Earth-100AU that we take into account, it will have only made as many orbits as Earth made in its first 4.5 million years, which wasn't even close to long enough to clear our orbit. And that was with considerable help from Venus, Mars, and Jupiter. So basically, there has to be a vacuum OR clutter out there, and we don't know which, but we won't find a million cubic AU of clutter consolidated into one body in only 4.5 million orbits.

Posted by: Alan Stern Jun 19 2008, 03:59 PM

QUOTE (JRehling @ Jun 19 2008, 05:27 AM) *
I guess the thought would be that that can't happen. For an Earth-sized object to be at 100 AU, the stuff for it to accrete out of has to be out there at about 100 AU. It couldn't have formed somewhere else and then made its way out there and just stopped unless there were something bigger out there. (A highly felicitous impact that significantly changed its orbit could do so, providing it didn't blast enough stuff off to once again reject the axiom.)

The period of an object at 100 AU is 1000 years. The volume of space around its orbit proportional to that of Earth is a million times as great. I'm certain the Earth hadn't cleared its orbit in 4.5 million years (the impacts on the Moon make that clear -- not by a long shot). So there's no reason to suspect that the "Early Heavy Bombardment" would even be over at that distance. Unless there wasn't enough stuff there for an Earth-sized object to accrete.



..Simpler than that. The IAU definition is about whether the object *has* cleared its zone. At 100 AU, in fact, even at 30 AU, an object of Earth's mass cannot do the job in the age of the solar system. It's just physics. It can't. Therefore, in the IAU's view, an Earth mass object at 30, 50, 100, or farther out is not a planet. And with that absurdity alone (never mind the trash orbiting with planets, never mind Pluto crossing Neptune's orbit, never mind the "voting" by 4% of the IAU, etc etc.), the IAU planet definition fails the most basic test-the one that keep people from laughing at it.

-Alan

Posted by: dvandorn Jun 19 2008, 06:18 PM

QUOTE (Alan Stern @ Jun 19 2008, 10:59 AM) *
..Simpler than that. The IAU definition is about whether the object *has* cleared its zone. At 100 AU, in fact, even at 30 AU, an object of Earth's mass cannot do the job in the age of the solar system. It's just physics. It can't.

Glad I finished reading the thread before responding, 'cause that's the exact point I was going to make.

You have to remember, everybody, that the Kuiper Belt is a (likely spherical) shell of bodies, not the remains of the originally super-flat accretion disk. We're out past the disk, where accretion followed different rules, and may still be occurring.

That volume of space contains so many bodies in so many trajectories that don't cross each other for billions of years at a crack, that even a gas giant would have a hard time clearing it all out in the 4.5 billion years the Solar System has existed, much less an Earth-sized planet. It's simply a function of volume -- correct me if I'm wrong, someone, but doesn't the volume of the Kuiper Belt exceed the volume of the entire Solar System from Neptune on in? And unlike the "main" system, which occupies a pretty flat plane (thereby limiting its useful volume when discussing neighborhood-clearing), the more spherical nature of the Kuiper Belt increases the volume to be cleared -- well, literally astronomically.

rolleyes.gif

-the other Doug

Posted by: ElkGroveDan Jun 19 2008, 06:24 PM

Perhaps Kuiper "Belt" is an unfortunately deceptive term then. Possibly Kuiper "Shell" would have been a better choice of terminology.

Posted by: Greg Hullender Jun 19 2008, 10:45 PM

QUOTE (Alan Stern @ Jun 19 2008, 08:59 AM) *
At 100 AU, in fact, even at 30 AU, an object of Earth's mass cannot do the job in the age of the solar system. It's just physics. -Alan


Thanks, Alan; that's what I was wondering about. I wasn't something I could work out here at home with Excel and a paper notebook. :-)

dvandorn: Why do you say the Kuiper Belt is a shell? I have not heard that before. It's certainly not how it's depicted in the Hayden Planetarium as of last Saturday. :-) Are you sure you're not thinking of the Oort Cloud?

--Greg

Posted by: nprev Jun 20 2008, 01:00 AM

Think he's onto something with that description, though, Greg.

At the very least, the Asteroid Belt is a relatively flat toroid due to solar tidal effects (in turn due to proximity to the Sun), which confines the majority of objects in the "traditional" Solar System to within just a few degrees of inclination with respect to the ecliptic.

I suspect that the Kuiper Belt planar distribution is at least tens of degrees above and below the ecliptic due to long, long orbital periods and much weaker tidal effects. It would be interesting to obtain rotation periods and axial inclinations for the larger KBOs. I suspect that many would not be tidally locked due to this, and fossil (because impact frequency has to be REALLY low compared to what we're used to down here by the fire) collision-induced rotation would dominate.

Posted by: alan Jun 20 2008, 03:21 AM

QUOTE (tasp @ Jun 18 2008, 08:29 PM) *
My apologies if someone else has thought of this first and I didn't notice (or if it is impossible . . . )
IIRC, quite a few objects out Pluto way seem to be resonant with Neptune. (3:2 springs to mind)
Are any other solar orbital periods suspiciously common amongst the remainder of the other objects ??
Or any commensurabilities??

In the Kuiper belt there are a number of resonances occupied, the 2:3 two orbits per every three orbits of Neptune (plutinos) which you've mentioned, the 1:2 which appears to mark the outer border of the Kuiper belt, also there are objects in the 1:1 (Neptune Trojans) 1:3, 2:5, 3:4, 3:5, 4:5, and 4:7 resonances with Neptune see http://www.cfa.harvard.edu/mpec/K08/K08M16.html
With Jupiter there are the Trojans 1:1, and the Hildas 3:2.
With Mars there are 4 Mars Trojans and possible a significant number in the 1:2 resonance, see http://www.fisica.edu.uy/~gallardo/marte12/mars1to2.html

Posted by: Greg Hullender Jun 20 2008, 03:24 AM

QUOTE (nprev @ Jun 19 2008, 05:00 PM) *
I suspect that the Kuiper Belt planar distribution is at least tens of degrees above and below the ecliptic . . .

Perhaps, but most found so far are within ten degrees of the ecliptic, based on what I found searching for "kuiper belt inclination". Lots of folks describe it as a torus (which is how the Hayden depicts it), but I haven't found a paper that described it as a sphere.

--Greg

Posted by: JRehling Jun 20 2008, 05:35 AM

QUOTE (Greg Hullender @ Jun 19 2008, 08:24 PM) *
Perhaps, but most found so far are within ten degrees of the ecliptic, based on what I found searching for "kuiper belt inclination".


The catch is that surveys can be biased to look for bodies near the ecliptic (which will be the best use of telescope time if your aim is to maximize discoveries). So we really don't have good data yet. The following page complains that some surveys haven't even published their approach, so it's impossible to know how biased the searches thus far have been:

http://www.obs-besancon.fr/TNOdb/node3.html


Posted by: Greg Hullender Jun 20 2008, 03:11 PM

If it's true that you maximize discoveries by looking for bodies near the ecliptic, then ipso facto the Kuiper Belt is not spherically distributed. Anyway, the catalog does show a handful of objects with highly inclined orbits, so it's not that no one is looking for them; they're just rare.

Back to the topic. Patryck has some nice diagrams of what he's talking about on his page:

http://harbor.scitec.kobe-u.ac.jp/~patryk/outerplanet/planet-en.html

I do wonder why his object has such an elliptical orbit though.

I found a no-subscription-required link to his last paper

http://xxx.tau.ac.il/ftp/arxiv/papers/0712/0712.2198.pdf

And I sent him an e-mail asking for a copy of the new one.

What's depressing is that a search for his name yields a huge number of psuedoscientific sites that try to cite his work as "proof" of their crazy ideas about how "Planet Nibiru" caused all the disasters in the Bible. Adding a "-nibiru" flag to a web search (minus in front of a term tells the search engine NOT to show pages with that word) cleans most of it up. This isn't Patryck's fault, of course, but it bothers me that I easily found pages and pages about the mythical Nibiru, but was unable to even learn the title of Patryck's new paper.

--Greg


Posted by: JRehling Jun 20 2008, 06:51 PM

QUOTE (Greg Hullender @ Jun 20 2008, 08:11 AM) *
If it's true that you maximize discoveries by looking for bodies near the ecliptic, then ipso facto the Kuiper Belt is not spherically distributed. Anyway, the catalog does show a handful of objects with highly inclined orbits, so it's not that no one is looking for them; they're just rare.


Actually, it could be spherically distributed and the searches still be biased if the searchers BELIEVE that it's not. But the fact that more objects are in prograde orbits than retrograde indicates some degree of nonrandomization. However, the fact that some highly inclined orbits have been discovered does NOT mean that searchers are looking outside the ecliptic -- inclined orbits cross the ecliptic.

The larger point is that the orbits definitely deviate from the ecliptic, though not fully randomly. But we can't use the discovered objects to characterize the population because of a bias in the searches. The mean inclination observed so far can't be used as a measure of the actual mean inclination.

Posted by: Pavel Jun 20 2008, 07:55 PM

QUOTE (David @ Oct 11 2007, 04:26 PM) *
Your task: Scour the fringes of the Solar System, and break up excessively large planets before they can pose a threat to astronomical law and order.

Also, you'll need to patrol neighborhoods of the established planets to make sure that they are cleared of any rogues.

Posted by: alan Jun 20 2008, 09:06 PM

QUOTE (JRehling @ Jun 20 2008, 01:51 PM) *
Actually, it could be spherically distributed and the searches still be biased if the searchers BELIEVE that it's not. But the fact that more objects are in prograde orbits than retrograde indicates some degree of nonrandomization. However, the fact that some highly inclined orbits have been discovered does NOT mean that searchers are looking outside the ecliptic -- inclined orbits cross the ecliptic.

The larger point is that the orbits definitely deviate from the ecliptic, though not fully randomly. But we can't use the discovered objects to characterize the population because of a bias in the searches. The mean inclination observed so far can't be used as a measure of the actual mean inclination.

Mike Brown's search for large objects extended a significant distance from the ecliptic, Eris and 2005 EL61 were discovered roughly 30 degrees north of the ecliptic.

Posted by: Greg Hullender Jun 21 2008, 11:31 PM

QUOTE (JRehling @ Jun 20 2008, 10:51 AM) *
Actually, it could be spherically distributed and the searches still be biased if the searchers BELIEVE that it's not.


Actually, no. If the objects were spherically distributed, then observers looking on the ecliptic would not find more objects than observers looking away from it. That would not be consistent with YOUR claim that looking near the ecliptic "will be the best use of telescope time if your aim is to maximize discoveries."

Or did you mean to include yourself among the biased researchers? :-)

--Greg

Posted by: nprev Jun 22 2008, 01:14 AM

I doubt that there actually is a spherical distribution of KBOs, though there certainly have to be a few in radically inclined orbits, perhaps even polar. What I expect is a normal distribution centered on the ecliptic, with a very gentle curve slope on each side...i.e., a really fat torus compared to the Asteroid Belt.

Posted by: brellis Jun 22 2008, 01:17 AM

To what extent can detection of as-yet-undiscovered SS objects be automated? Couldn't a 'puter follow the images obtained from a craft surveying the entire celestial sphere, and automatically flag objects that move between images?

Posted by: nprev Jun 22 2008, 01:22 AM

Well, at least the NH team will be investigating the region achievable post-Pluto with unprecedented detail.

Kinda like the idea of a dedicated KBO finder mission, but it might have to stare at a given patch of sky for quite some time to pick anything up (esp. very distant objects), and there's a lot of sky to cover.

Posted by: JRehling Jun 22 2008, 07:49 AM

QUOTE (Greg Hullender @ Jun 21 2008, 04:31 PM) *
Actually, no. If the objects were spherically distributed, then observers looking on the ecliptic would not find more objects than observers looking away from it.


I never said otherwise.

QUOTE (Greg Hullender @ Jun 21 2008, 04:31 PM) *
That would not be consistent with YOUR claim that looking near the ecliptic "will be the best use of telescope time if your aim is to maximize discoveries."


Again: Researchers will concentrate on the ecliptic if they BELIEVE that that maximizes discoveries, so a concentration of discovered bodies near the ecliptic is not evidence that there is no spherical distribution. It may be true or not true, but the pattern of discovered bodies doesn't prove that.

I do not believe that there is a spherical distribution, so I believe that the researchers are correctly directing their surveys... if their goal is to maximize the number of discovered bodies.

It is not strictly necessary to look anywhere but the ecliptic in order to characterize the obliquity of the population, but it is necessary to publish the details of the survey in order to translate the discoveries into the obliquity of the population. The page I linked to notes that this has not been adequately described by the surveys they cite.

Posted by: dvandorn Jun 22 2008, 04:08 PM

Okay -- let's look at this from the back forward, rather than as a snapshot of "right now."

The Solar System accreted from an accretion disk, correct? Every body that accreted from this disk occupies a pertty narrow range of obliquities, within less than 10 degrees of one another. This covers everything from Mercury out to Neptune. It includes all but the smallest of the asteroids, as well.

Then we find a population of bodies that does *not* fall neatly into that ecliptic plane. What is the most natural conclusion to be drawn from that? The conclusion I draw is that the accretion disk had ceased to be a flat disk by the time we got out that far from the sun. Lack of tidal forces and all that.

So, matter that is still gravitationally attached to the Sun but beyond the forces that draw the matter into a disk -- in what way would it form itself? I would think physics would demand that such matter would arrange itself as a sphere around the Sun. Just as the farther-out shell of cometary debris, the Oort cloud, has.

Now, I will admit that I haven't read each survey. But from the results that get talked about (i.e., the discovery of pretty much any body large enough to have been found thus far), not only are we *not* seeing a majority of these objects in the ecliptic, my understanding is that *none* of the more massive objects have been found in anything except inclined orbits.

What does it say about the general distribution of KBO objects when none of the larger members of that population thus far discovered orbit within the ecliptic? How can that be worked back into a population that has its greatest density in the ecliptic with a population that thins out as you move away from the ecliptic (i.e., a torus)?

This is the logic chain that leads me to believe that the KBO population distribution is closer to spherical than to a toroidal "belt."

As with all things, I could, of course, be wrong... rolleyes.gif

-the other Doug

Posted by: Del Palmer Jun 22 2008, 04:32 PM

QUOTE (dvandorn @ Jun 22 2008, 05:08 PM) *
Then we find a population of bodies that does *not* fall neatly into that ecliptic plane. What is the most natural conclusion to be drawn from that? The conclusion I draw is that the accretion disk had ceased to be a flat disk by the time we got out that far from the sun. Lack of tidal forces and all that.


Er, not quite. You need a lot of energy to escape the ecliptic plane. Those high-inclination bodies are known as "scattered-disk" objects -- they were most likely formed in the ecliptic plane but were gravitationally tossed into such odd orbits by Neptune.

QUOTE
Just as the farther-out shell of cometary debris, the Oort cloud, has.


Likewise, those objects are believed to have been put there by Jupiter and Saturn...

Posted by: dvandorn Jun 22 2008, 05:10 PM

QUOTE (Del Palmer @ Jun 22 2008, 11:32 AM) *
You need a lot of energy to escape the ecliptic plane.

Only if you started out there in the first place.

Also, I have an image of an evolving Solar System that resembles many of the stars-with-disks that Hubble has imaged. Most of these have been in "nursery" nebulae, and the new star is in the process of clearing the smallest gas and dust particles from its vicinity. There is usually a half-spherical "bow shock" effect along the interface between the star's out-pushing solar wind and the dust and gas in the nebula, often defined by the star's trajectory through the nebula.

So -- you have a newly-formed Sol with its accretion disk forming the majority of the Solar System, and a half-sphere shell of bow shock between its solar wind and the gas and dust of the nebula in which it formed. Thus you have accretion going on in two different places, out of two different basic types of materials, one in a tightly planar disk and another along the surface of a spherical area of interaction between the star's violent outgassing and the womb of the nursery that gave it birth.

In such a genesis scenario, I can easily see population of outer system objects being created in spherical shells at various distances from the Sun, remnants of conditions throughout the first few million years after Sol formed.

Again -- I'm not running this through mathematical models. I'm just putting together what I've learned with what I've observed. And while I *do* understand that most current theories still try and keep the genesis of all SS objects as within the accretion disk and discount the possibility of non-planar accretion, I guess I'm saying that my temptation is to describe that thinking as "clinging to" a planar-only genesis concept. I've seen almost nothing in print on the concept of accretion along a bow shock wave in such curcumstances.

In my little gedanken-model, here, I see the current state of the outer System as a depleted version of a young system, which would contain a nice little set of worlds accreted out of a disk and a vast, low-density cloud of "wastage" formed roughly into a sphere around the star. Gravitic resonances from the planar System as well as perturbations by passing stars will have altered it significantly over the life of the System. But my image is still of a roughly spherical shell of only lightly assembled flotsam.

-the other Doug

Posted by: Greg Hullender Jun 24 2008, 03:32 PM

Patryck responded to my e-mail:

"Thank you for your email and interest in my research. I believe there was a mistake in the news because I have not written a new paper to the Astrophysical Journal. The results are based on the same paper published in the April issue of the Astronomical Journal."

Oh well. At least we know.

--Greg

Posted by: icaru Sep 21 2008, 08:09 AM

Hello everybody!

I'm a student in an engineering school in Paris, France.


I have to find a subject of contreversy ( like "the dangers of cellulars phones ) for a work. In a french review ( Ciel et espace ), I read an article about Aernus and I found more informations on internet through the work of Patryk Lykawka and Tadashi Mukai.
It's very interesting, I find a lot of informations coming from Patryck Lykawka.


My subject mut be a contreversy, so: Do you know the name of scientist, journalists( from serious magazines, not from a people magazine...) or people who don't agree with Patryk Lykawka and don't believe in the existence of a new planet?
If you have websites talking about Aernus(for and against this theory), I would be interested too.
I ask this question because I have the impression that Mr Lylawka is the only scientist interested in this subject. unsure.gif



Thank you for any replies. smile.gif


PS: Sorry for my mistakes !

Posted by: Greg Hullender Sep 21 2008, 03:12 PM

Have you looked at issues of Astronomical Journal immediately following the one in which Patryck's article appeared? Find those and carefully look at the letters to the editor. If there is someone with a strong contrary opinion, that person will likely have written a letter within a month or two of Patryck's paper, explaining why he or she doesn't believe it. You could also e-mail Patryck and ask him yourself.

--Greg

Posted by: alan Sep 21 2008, 03:41 PM

Patryck Lykawka proposed his planet as an explanation for the dynamical structure of the Kuiper Belt, particularly its cutoff at roughly 48 AU. I've seen Alessandro Morbidelli listed among the authors of a number of papers modeling the primordial origin of this structure, although I don't remember him specifically mentioning Lykawka's explanation. Searching for some of his papers (try here : http://adsabs.harvard.edu/abstract_service.html ) would be a good place to start.

Posted by: icaru Sep 21 2008, 08:37 PM

Thank you for your answers!


Greg Hullender, I found the name of scientists who don't agree with Patryk in the answer of Patryk for a journalist french!
Thank you for your help!




In fact I must talk about a controversy tomorrow to my teacher during 5 minutes! If the subject is interesting in relation to the subject of my "colleagues"(the hydrogen for cars and an other : the dangers of antidepressants), we'll continue on Aernus. I'm in a hurry, so I prefer waiting before sending an e-mail to Patryk Lykawka. rolleyes.gif


Bye bye! wink.gif

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