Talk:Kuiper belt/Talk:Kuiper belt archive 1

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[edit] KBO table

It turns out that the mean distance values and diameter estimates of these objects are noisy. We can cite the mean distance values from the Minor Planets Circular (which has no search engine itself, unfortunately). Brian Marsden does not share his error bars, so we cannot know how accurate the values are. But, at least there is one canonical source for the numbers.

The diameter estimates are even worse. They come from the absolute magnitude, which is moderately accurate, combined with the albedo, which for KBOs seem to be random guesses. Ordering the table by diameter estimates may be misleading.

Should we just display absolute magnitude in the table, and sort by that ? The downside is that very few people would understand what the parameter means. -- hike395 10:03, 21 Sep 2003 (UTC)

Why not include a paragraph explaining what you've just said? Wouldn't that sort out any confusion? :) Dysprosia 10:05, 21 Sep 2003 (UTC)

[edit] Trans-Neptunian vs. Kuiper Belt

Current revision extensively uses TNO over KBO. Which is acronym preferred by astronomers? --- hike395 06:40, 5 Oct 2003 (UTC)

"KBO" would probably be better, since this is an KB, and not a TNO article. I used TNO thruout since "Kuiper" is not as good a name for the belt, but TNOs do of course include Oort cloud objects. How's the 2003-10-06t22:12z edit? Also, are subscript object numbers (1992 QB1) depreciated? - Jeandré, 2003-10-06t22:17z

Thanks for clarifying the article, Jeandré! It's much cleaner now. As for subscript object numbers, I think that it is uncommon. Much of the information on minor planets is still published in ASCII text files (for example, see [1] for the official list of TNOs from the Minor Planets Center). Thus, designations seem typically not to have subscripts. Even book-published ephimerides don't use subscripts (although this statement is relying on 15-year-old memories that may be incorrect).

[edit] Do we need separate articles?

The pair of articles Kuiper belt/Trans-Neptunian objects bothers me. As far as I can tell, the only TNOs that are not KBOs are Oort cloud objects, which have never been observed. This article is more fleshed out than the TNO article, but I don't know how to combine them rationally, since they aren't identical subjects. Should we copy over all of the good stuff? The articles will drift apart, anyway...

What's the precedent in Wikipedia? How do we handle levels of a taxonomy when one level is dominated by one leaf node below it? -- hike395 01:23, 2 Feb 2004 (UTC)

I don't think there's anything wrong with having the Trans-Neptunian objects article become relatively puny. It may wind up only a glorified disambiguation page linking Oort and KB, but considering how many non-glorified disambiguating pages there are it won't be the worst of the lot. :) Now that I think of it, there's at least one other astronomical article that deserves mention in TNO that's neither Oort or KBO; Nemesis (star). I'll add that in. Bryan
Whether glorified disambiguation or not, KBO is a proper subset of TNO so we need separate pages. However, if all (or nearly all) the known TNOs are KBOs, this does not answer the question of whether these objects should be discussed in the Trans-Neptunian or Kuiper belt pages. Joelwest 14:31, 20 Mar 2004 (UTC)

[edit] Rewrite issues

Some source pages for 2004 DW: http://www.gps.caltech.edu/~chad/2004dw/ (calls it a plutino) and http://www.hohmanntransfer.com/mn/0402/19.htm#04dw (cubewano).

The 2nd paragraph could do with some rewording: the 2004 DW mention was just squeezed in.

I don't think we should link "2004 DW" until it has a post code name number e.g. 2004 DW42 (what is that number?), or a number e.g. Quaoar's 50 000 (what is that number called?). We can later move the article when it gets a religious proper name. - Jeandré 2004-02-20t10:50z

Thanks for updating the article. To answer your question, 2004DW is a number assigned to an apparition: a minor planet that is viewed over the course of one or two nights. The apparition does not have a very well determined orbit. Researchers go through a "pre-covery" process, which links together apparitions over a number of years. Once those are all linked together as one body, the orbit is much better determined and the minor planet considered "discovered" and given an official IAU number. The discoverer (the person who made the final apparition that linked together all previous ones) is then given a chance to name the object, subject to IAU approval.
2004DW is a perfectly valid apparition designation: the D means it is discovered in the 7th or 8th week of 2004, while W means that it was the 23rd apparition found.. You only start to see the extra numbers on the end when more than 26 apparitions are seen in a 2 week period, which almost always happens nowadays.
-- hike395 14:42, 20 Feb 2004 (UTC)

[edit] Sedna

I see Sedna has been added to the list. I was under the impression that it was actually beyond the Kuiper belt... Evercat 19:44, 14 Mar 2004 (UTC)

It's definitely not an Oort cloud object, and I believe Oort and Kuiper are the only two divisions. Currently, anyway. These things are still somewhat ill-defined. Bryan 19:58, 14 Mar 2004 (UTC)
There is controversy over whether Sedna is Kuiper or Oort, and the current Sedna discussion now reflects that. Joelwest 14:31, 20 Mar 2004 (UTC)

Well, this page says the KB goes to about 50 AU, but also gives Sedna's distance as 67 AU... Evercat 20:27, 14 Mar 2004 (UTC)

The Oort cloud page says the Oort cloud doesn't begin until 50,000 AU, so I think KB is still a more likely classification for it. Does anyone know whether the 50 AU limit is based on some objective definition, or if that was simply as far out as anyone had detected KBOs to this point? Bryan 22:01, 14 Mar 2004 (UTC)

Note that the semi-official Sedna page says it's not a KB object... Evercat 00:58, 15 Mar 2004 (UTC)

Going to have to update the Oort cloud page, then. 50,000 AU is a few orders of magnitude off. :) Bryan 01:27, 15 Mar 2004 (UTC)

Well that page calls Sedna an inner Oort cloud object. :-) Evercat 01:29, 15 Mar 2004 (UTC)

[edit] Is it really Kuiper's belt?

Dan Green of Harvard has posted a scathing critique of the name "Kuiper Belt", far beyond the Edgeworth issue. He uses the terms "Cubewano-belt" or "Leonard/Edgeworth/Kuiper/Whipple-belt". He seems to be alone right now.

I don't think this questions whether we should have an entry or call it by "Kuiper belt", the commonly accepted usage. But do we want to acknowledge the controversy? Link to his page? Does anyone have knowledge of the issue beyond Green's complaint? Joelwest 14:31, 20 Mar 2004 (UTC)

Kuiper belt is the most common name, so that should be used in Wikipedia, as per the Naming conventions. As for the name controversy, it should in my opinion definitely be addressed in this article. Only when standard use changes to Edgeworth-Kuiper or whatever-Kuiper belt should the term be changed everywhere. — Jor (Talk) 14:41, 20 Mar 2004 (UTC)
I don't think the word "controversy" (n: a dispute where there is strong disagreement; "they were involved in a violent argument" (WordNet 1.6)) should be used. "Kuiper" is simply a strange name to use when one looks at the evidence presented; other suggestions are given but there is no mention of "Leonard/Edgeworth/Kuiper/Whipple-belt" in the article. - Jeandré, 2004-04-10t03:15z

[edit] Kuiper belt around other planets?

Is the name Kuiper belt unique to the belt of asteroids around the Sun, or can it be expanded to included other asteriod belts? And if not, what is the name given to the Kuiper belt around other planets? -- Ec5618 23:07, May 15, 2005 (UTC)


There are no Kuiper belts around planets. They only exist around stars. I presume that the term is used for any such belt and not just the one around our sun.


Whats the difference between the rings around Saturn and the Kuiper belt?

Well, here's a couple to start with:
  • Kuiper belt (like any asteroid belt) contains lots of large gravitationally bound bodies - right up to the size of Pluto, rings don't. The largest ring particles are at most rocks a couple of meters across, while many rings are composed purely of tiny dust-like particles.
  • Rings are dense enough to block an appreciable proportion of the light passing through them. Satrurn's rings block most of the light. The Kuiper belt is completely transparrent, and the distances between bodies in the Kupier belt (and in the asteroid belt) are huge. For example when New Horizons flew by an asteroid at a distance of 100,000 km, it was considered a "close" flyby. You can fly through the Kuiper belt without worrying over hitting anything appreciable, while if you were to fly through rings your spacecraft would crash.
Deuar 21:43, 22 June 2006 (UTC)

[edit] Discovery credit for 2003 EL61

http://groups.yahoo.com/group/mpml/message/15131 and http://groups.yahoo.com/group/mpml/message/15132 make it very clear that Ortiz et al. are the sole discoverers of 2003 EL61. There are no co-discoverers. Brown et al. had been observing this same object without reporting its position to the Minor Planet Center. They lost any right to discoverer status after Ortiz et al. reported their positions. Brown himself has admitted himself that Ortiz et al. are the rightful discoverers.

Actually, Brown now questions the discovery claim by Ortiz et al. [2]

[edit] Plutinos etc

Looking through the various Wikipedia entries, it appears that

  • Plutinos are Kuiper belt objects in a 3:2 resonance with Neptune
  • Cubewanos are Kuiper belt objects that have no resonance with Neptune
  • Scattered Disk Objects are Kuiper belt objects with an extremely eccentric orbit

A couple of questions: 1) What is the name for Kuiper belt objects in a non-3:2 resonance with Neptune? 2) Is there yet an official dividing line between DCubewanos and Scattered Disk Objects?

1) You mean in other resonances, like 1:2 or 3:4? I've seen 1:2-resonance objects called "twotinos". 1:1-resonance objects are of course Neptune trojans.
2) According to this SDOs are KBOs whose semimajor axes are greater than 50 AU plus those whose semimajor axes are from Neptune's orbital distance to 50 AU with perihelion distances less than 25 AU.--Jyril 12:56, August 2, 2005 (UTC)
(SDO)...objects with perihelia in the ∼35 to 40 AU range and characteristically large eccentricities and inclinations; from Jewitt [3]] Eurocommuter 23:55, 8 February 2006 (UTC)

[edit] List of largest KBOs

Like it has been said above, it is horrible. Some of the values would require ridiculously low albedos (I suspect that they're just upper limits from nondetections). For example the absolute magnitude of Template:Minplan is at the moment only 49th. Also some clearly large objects, like Template:Minplan are missing.

Here's a list of all at the moment known KBOs with absolute magnitudes less than 4.0. Diameters are estimated from the albedo range from 1.0 to 0.03 [4]:

                     H    diameter    constraints [5]
        2003 UB313  -1.2  2300-13300  < 3500 km (3000 km, p=0.6)
        Pluto       -1.0              2320 km (p=0.6)
        2005 FY9     0.0  1300- 7700  50%-75% Pluto (1700 km, p=0.6)
        2003 EL61    0.4  1100- 6400  70% Pluto (1400 km, p=0.6)
(90377) Sedna        1.6   640- 3700  <1500 km ? (p>0.18)
(90482) Orcus        2.3   460- 2700  ~1500 km ? (p=0.09)
        Charon       1                1270 km (p=0.4)
(50000) Quaoar       2.6   400- 2300  1200+-200 km (p=0.12)
(28978) Ixion        3.2   300- 1800  1650+-165 km (p=0.09; d is probably gross overestimation)
(55636) 2002 TX300   3.3   290- 1700  (840 km, p=0.12)
(55565) 2002 AW197   3.3   290- 1700  890+/-120 km (p=0.1)
(55637) 2002 UX25    3.6   250- 1500  (730 km, p=0.12)
(20000) Varuna       3.7   240- 1400  900+/-140 km (p=0.07+-0.02)
        2002 MS4     3.8   230- 1300  (670 km, p=0.12)
        2003 AZ84    3.9   220- 1300  (640 km, p=0.12)
(84522) 2002 TC302   3.9   220- 1300  (640 km, p=0.12)
...
(15874) 1996 TL66    5.4   110-  640  (319 km, p=0.12)

For those without given diameters, I've used Quaoar's albedo value 0.12.

--Jyril 15:15, August 2, 2005 (UTC)

I certainly wouldn't object to a substantial rewrite. Template:Trans-Neptunian dwarf planets should be simultaneously updated to reflect only the real biggies. -The Tom 19:02, 2 August 2005 (UTC)
I thought 2003 UB313 was a KBO, and changed the article to reflect that, but after closer reading of its article and the SDO-page it seems to be a scattered disc object, so I'll revert my changes. Feel free to bring them back if I misunderstood. Amaurea 10:53, 23 December 2005 (UTC)

[edit] Why is it called Kuiper?

FTA In 1951 Gerard Kuiper suggested that objects did not exist in the belt anymore... The belt and the objects in it were named after Kuiper after the discovery of (15760) 1992 QB

I don't get it. If Kuiper said that objects did not exist in the belt why was the belt named after him?!! I just checked the history and this is where the change was made in the article (2003) : http://en.wikipedia.org/w/index.php?title=Kuiper_belt&diff=1459803&oldid=1459783 --156.34.78.219 06:02, 5 October 2005 (UTC)

Sounds rather fishy to me too. Possibly this is a misinterpretation of Kuiper's emphasis on the belt as the original location of the short-period comets observed in the inner solar system. 216.160.109.205 06:38, 6 October 2005 (UTC)
See #Is it really Kuiper's belt? — Jeandré, 2005-10-25t12:32z

I was going to ask a similar question. It seems as if this is worded incorrectly. What exactly did Kuiper say about the belt? Is this trying to say that he didn't think there would be any more objects discovered? Or that the nature of the belt wasn't what was previously asserted? Jasongetsdown 22:14, 13 December 2005 (UTC)

I've replaced the passage with a widely verified statement of Kuiper's involvement, that he proposed the belt is the location for short period comets. The previous sentence seemed to be nonsense. Jasongetsdown 22:27, 13 December 2005 (UTC)

[edit] 1992

Over 800 Kuiper belt objects (KBOs) (a subset of trans-Neptunian objects (TNOs)) have been discovered in the belt, almost all of them since 1992.

Why? I think the answer involves the Hubble space telescope, but I'm not sure. Please provide a detailed answer to this question in the article. Thank you. - RoyBoy 800 21:40, 1 December 2005 (UTC)

Only two TNOs (Pluto and Charon) were discovered before 1992. Hubble has detected only a few previously unknown trans-Neptunian objects, vast majority of TNOs are found during ground-based sky surveys. Hubble with its tiny field of view is very impractical searching new objects.--Jyril 22:41, 1 December 2005 (UTC)
Should have known that, thanks... and why since 1992? Because computers were employed in conjunction with sky surveys to find new objects? - RoyBoy 800 15:02, 8 December 2005 (UTC)

[edit] Pronunciation

The pronunciation guide in the artile isn't very useful. Does the 1st syllable rhyme with "eye" or is it pronounced like "key"? I'm not trying to be nitpicky; I came to the article because I was curious about exactly this point. See Wikipedia:Manual of Style (pronunciation) for guidance on this. --דוד ♣ D Monack 08:34, 17 December 2005 (UTC)

[edit] What was formed in situ?

"Modern computer simulations show the Kuiper belt to have been formed by the work of Jupiter, the young Jupiter having used its considerable gravity to eject smaller bodies which didn't all escape completely, and also having been formed in-situ." -- I'm trying to revise this (IMHO) odd and unclear sentence, but I can't understand just what is supposed to have been formed in-situ. Jupiter? The Kuiper belt? The smaller bodies? -- Writtenonsand 05:18, 21 January 2006 (UTC)

[edit] Structure

Further rationalisation is required, I believe, in order to clearly separate the legacy theories from the times the terms (Kuiper belt, classical objects, scattered disk) were coined with the results of current research. In addition, I feel, a further re-grouping of the existing material would be useful, into sub-sections

  • (modern) theories of the origin (with models explaining the distribution)
  • what is known on colours (spectral characteristics) with current thinking about the physical characteristics. Eurocommuter 11:02, 22 February 2006 (UTC)

[edit] Someone please fix this

The only occurrence of the phrase "Kuiper Cliff" is in a sentence which already assumes that the term has been defined elsewhere. Ken Arromdee 02:39, 16 March 2006 (UTC)

[edit] Assessment of this article for Version 0.5

We plan to use this piece in the test CD release of Wikipedia. This article looks to be A-Class on the assessment scale to me, i.e., ready to go to peer review (or WP:GAN first, if you prefer). However, I'm not familiar enough with the topic to know if something major is missing. If there is a major topic (i.e. that should be >15% of the article) that is completely missing or glossed over, could someone change "class=A" to "class=B", and leave a note here why? Thanks, Walkerma 16:10, 12 June 2006 (UTC)

The Oort cloud (if it exists) is too far away to provide short-term comets, and due to the loss of material on every close pass to the sun, short-term comets can't be billions of years old. So, the Kuiper belt was proposed to fill that gap. Now, we've found objects there, but they aren't proto-comets; hence, they are not a part of the "Kuiper" belt. The article admits that "some scientific groups" recommend not even using the name, due to the controversy, but makes no further reference to it, and does not explain it. Mdotley 15:53, 25 August 2006 (UTC)
Yes, the article reads as a mix of some remaining legacy content with today's feel. The two are not blended so the old sticks out. The small problem is that most researches are themselves shy to stir the terminology. (look what happened to Pluto discussion). So not so many people point out that for example Kuiper specifically did not believe in big objects that have been found in his Belt (e.g. Jewitt does). It proved not be the Belt by the way, but a thick torus. Etc, etc. New classification schemes are hopefully emerging (e.g. Elliot 2006). The shocking reminder for these theories is the opening diagram we kept (1998!). The article should go to a review, the content clearly separated into the old and new (including observational facts).A few summary, technically accessible peer-reviewed scientific papers exist to serve as solid refs. I would contribute to the review if decided. Eurocommuter 09:25, 9 September 2006 (UTC)

[edit] Losing information on the various classes of KBOs

See Wikipedia:Articles for deletion/Twotino. Uncle G 07:52, 9 September 2006 (UTC)

[edit] Why are Scattered KBOs separated?

So far, the supposedly strict usage that the latest version of the article makes of the term KBO, makes little sense and is not in accordance with astronomers' usage. Not just Mike Brown calls Eris a KBO [6] but also Jewitt [7] considers all to belong to the Kuiper Belt.

If Scattered KBOs should be separated because part of their orbits are beyond the conventional limits of the KB, then also should Plutinos, whose orbit also goes beyond those limits by the inner edge: Pluto and family cross the orbit of Neptune.

It's much more accurate in my opinion to group Classical KBOs, Plutinos and Scattered KBOs into the KB, as most astronomers actually do. (Sedna is not a KBO though). --Sugaar 16:24, 23 September 2006 (UTC)

Grouping Classical KBOs, Plutinos and Scattered KBOs into the KB makes it a blanket category for almost all Trans-Neptunian Objects (apart from Sedna and at most a couple of other objects in the "Extended Scattered Disc"), and categorising an object as such gives very little physical information. On the other point you mention: the Pluto family are being clearly separated as plutinos. Deuar 20:05, 27 September 2006 (UTC)
I see. But actually that's the case with our current state of knowldege: Trans-Neptunian objects are KBOs and Sedna (so far). KBOs are of three types: Plutinos, classical KBOs and scattered KBOs, sometimes called "scattered disk objects" though there's no real region called scattered disk (at most it is a subregion of the KB).
My point is that, when astronomers of the cathegory of Brown and Jewitt consider scattered objects to be just a type of KBOs, we sould follow their lead, until they (the astronomical community) change their mind. Making these kind of arbitrary separaations is very confuse and not Wikipedian (it's POV). --Sugaar 03:24, 28 September 2006 (UTC)
I certainly agree with your sentiments of not creating "wikipedia terms". The difficulty here is that there doesn't appear to be an overwhelming consensus as to the terminology among the astronomers. While e.g. Brown and Jewitt may use KBO as a blanket term, others don't. As evidence of widespread professional use check out the following (obtained by a google search)
  1. The Minor Planet Centre publishes a List Of Centaurs and Scattered-Disk Objects that specifically excludes "Kuiper belt objects" but contains e.g. both Sedna and Eris.
  2. The Planetary Society, a large and reputable professional+amateur+armchair astronomers organisation that is run by professional astronomers separates KBOs from Scattered disk objects on its Trans-Neptunian Objects fact page
  3. A search for the phrase "scattered disk object" on Google Scholar turns up 37 hits in scientific publications.
  4. Numerous other professional astronomy websites separate out the Scattered Disk objects. (Just search the web, e.g. here's one of the first to come up on the Google list).
In conclusion, separating out SDOs is not an arbitrary wikipedia decision but reflects the views of many and/or most professional astronomers, and as such is fine. If a consensus were to crystallize that they are a mere subset of the KBOs then we should then of course adapt the articles, but this will probably take the professionals a few years to sort out one way or the other. Until then, the current division is fine and also useful for illustrative purposes − the "typical" SDO orbit is qualitatively different from a "typical" classical KBO orbit, even if the boundary is indistinct. Deuar 14:12, 28 September 2006 (UTC)
I see your point.
Still it would probably be best, to make a short explanation of the issue in both articles. Maybe a brief section explaining that SDOs are considered by some astronomers as KBOs, while others don't, explaining maybe the main differences (inclination basically, am I wrong?) that cause them to be classified in a separate group.
Btw, how does anyone dares to suggest that Sedna, an object that is very well alligned with the eccliptic could be an SDO? Well, never mind. Just thinking loud. --Sugaar 15:49, 3 October 2006 (UTC)
I agree − it would be a good idea.
From what I know, the distinguishing features are a semi-major axis over ~45 AU, and a high eccentricity. In e.g. Image:TheKuiperBelt_100AU_SDO.svg, you can see the "classical" KBOs clustering in a compact bunch around 44 AU (± a few AU), and the scattered disc at larger distances. The classical KBOs appear in "hot" and "cold" populations, with the cold clustering at low inclinations. Then there is the other issue of whether the perihelion is near Neptune's orbit. In almost all cases it is, but a few bodies such as Sedna do not approach Neptune at any time. These then have been dubbed the "extended" scattered disc, because it is not clear how their orbits have become the way they are. It could not have been simple perturbations by Neptune. Deuar 20:12, 4 October 2006 (UTC)
I don't have a reference handy, but the problem with Sedna is that it's Perihelion is too far from the sun (or Neptune) to think of it as somehow scattered out of the Kuiper Belt in the usual way. Hence throwing around the talk about it being from the Oort cloud. There are other ways out of this (scattered disk object perterbed by a nearby star apart from the sun on a close encounter) and it's still far from figured out. WilyD 20:27, 27 November 2006 (UTC)

[edit] Kuiper cliff

Kuiper cliff redirects here, but isn't mentioned in the article. Serendipodous 15:02, 25 November 2006 (UTC)

Good point, it's not explained in the article (it is mentioned, though but it's used incorrectly or the sentence needs some work, "Discoverer Michael E. Brown, for instance, has referred to Eris as a KBO, despite it having a mean orbital radius of 67 AU, well clear of the Kuiper cliff." maybe "placing it well outside of the Kuiper cliff?"). My astronomy is too old to edit this, probably. KP Botany 23:39, 26 November 2006 (UTC)

The Kuiper cliff is expected from recent work on the formation of the Solar System. Growing evidence points to the Sun forming in a crowded environment (a stellar cluster like the Orion Nebula). In such environments, the disk around the young Sun would be truncated by starlight from the very hot, very bright stars in the vicinity (in Orion, these are the Trapezium stars, aka Theta Ori 1). In addition, these hot stars explode as supernovas on several-million-year timescales. The shock wave from these supernovas would also strip the outer edge of the protoplanetary disk. I'm in the process of reading up on this work. Once I have citations and text, I'll add it to the "Kuiper cliff" section. The Astrogeek 16:00, 24 December 2006 (UTC)

The meteor guys (I believe) there was a very nearby supernova at some point while planetesimals were forming (or at least, centimeter dust grains). That said, I'm sure I could dig up alternative mechanisms for the cliff - it's by no means universally agreed upon as to the cause, right? WilyD 16:29, 24 December 2006 (UTC)

[edit] Is the largest known Kupiter Belt object Triton?

It would seem to me that Triton would be the largest KBO (although technically it's no longer in the Kupiter Belt). Is this accurate? —The preceding unsigned comment was added by 76.185.18.21 (talk) 01:17, 7 December 2006 (UTC).

  • The answer you're looking for is probably yes. WilyD

[edit] Serious source

Anyone know when `Transneptunian Objects', Barucci et al. eds., University of Arizona Press is coming out? WilyD 18:42, 23 April 2007 (UTC)

[edit] Can we find a better lead image?

The image at the top of this article is more an image of the Oort cloud than the Kuiper belt. Serendipodous 07:41, 1 May 2007 (UTC)