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Dimensions

The infobox says that Spitzer telescope observations led to the result 1150 +250/−100 km. However, it is not clear, which of the three dimensions is meant by this figure. This figure is mentioned only in the infobox, I think there should be also some more detailed information in the main body of the article. Jan.Kamenicek (talk) 13:03, 17 January 2009 (UTC)

I assume that it is referring to an average (via the calculation method used) axis. Spitzer did not resolve the object outright. -- Kheider (talk) 20:17, 19 January 2009 (UTC)

I see, thanks. However, I believe that this figure should be somehow mentioned in the article, too. Jan.Kamenicek (talk) 20:31, 19 January 2009 (UTC)

Well, this is a feature article and so I believe that such a crucial thing as the dimensions are should be described there in detail. Could the authors, who certainly have more information on the topic, fix it, please? Thank you very much. Jan.Kamenicek (talk) 21:26, 1 February 2009 (UTC)

I have commented on the albedo dispute between Rabinowitz 2005 vs Stansberry 2007. There really isn't a problem, it is just that difference methods will come up with different albedos and thus different sizes. (edit) -- Kheider (talk) 22:53, 1 February 2009 (UTC)

Thank you. However, now there is a different number in the caption to the Haumea picture (Spitzer measurement) and a different number in the main body of the article (Keck?? measurement). At first I decided to add the figures to the article myself, but I found out that the given source links just to the abstract of an article, which gives some information about the length, but no info about the other sizes. Could it be added as well? This info should not be missing. Thank you. Jan.Kamenicek (talk) 21:12, 2 February 2009 (UTC)

The sources given do link to the arXiv page where the .pdf of the article is available for free download, if you would like to read the full articles. But I'll see if I can get on to it in a few hours and add a set of sentences with more explanation about the size and uncertainties involved. Iridia (talk) 22:37, 2 February 2009 (UTC)

I think you are expecting a single right answer when there currently isn't one. The true size is only estimated and the ratio of the axes is also estimated. Rabinowitz 2005 (Table 5; Page 24) gives a size of 1960x1518x996 (shown as semi-major axes of a₁=980, a₂=759, a₃=498) based on an albedo (P_v) of 0.73. Stansberry 2007 gives a diameter of 1150 based on a measured (brighter) albedo of 0.84, thus generating a smaller diameter. The phase angle can also affect the albedo. The albedo and absolute magnitude of the object determine how large it is. -- Kheider (talk) 23:36, 2 February 2009 (UTC)

I expanded it - took a while to get the references straight, since they often describe slightly different things. Can we please discuss which numbers from which paper should now go in the info box? Iridia (talk) 10:36, 3 February 2009 (UTC)

We have "The first model produced after Haumea's discovery was calculated from ground-based observations of Haumea's light curve at optical wavelengths: it provided a total length of 1350
₋₁₀₀ km (Stansberry2007/Spitzer) and a visual albedo (p_v) greater than 0.6. (Rabinowitz2005)" Stansberry2007 (ref:Spitzer, Table 4) is quoting Rabinowitz 2005 (Ra05) as a source. The first model was simply Rabinowitz 2005. -- Kheider (talk) 16:52, 3 February 2009 (UTC)

True; but they gave an uncertainty from processing Rabinowitz 2005's data, which put the measurement in the same format as the Spitzer one. Now modified. Iridia (talk) 05:39, 4 February 2009 (UTC)

Thanks, now I think the information is complete. As for the infobox, I would suggest the most recent finding. Jan.Kamenicek (talk) 22:26, 3 February 2009 (UTC)

I think Rabinowitz 2005 and the latest paper are giving the same approximate size since the true size is unknown. Lacerda 2008 quotes a lot of data from Rabinowitz 2005. The difference is negligible. Lacerda's numbers are intentionally so round as to suggest it is only a best guess. Either way I think the Spitzer data should stay. There is no reason not to quote multiple sources and numbers. I think the size of the object appears to be better discussed (for casual readers) in Rabinowitz 2005. -- Kheider (talk) 23:53, 3 February 2009 (UTC)

Yes, definitely. They are quite different calculations, so it's good to have both. I dropped the Lacerda ones from this context.Iridia (talk) 05:39, 4 February 2009 (UTC)

If you think we should not round quite so much on the triaxial dimensions, we can increase the number of significant figures; but I'd rather have easy-to-read numbers in the body of the article, and put with them a linked note specifying the numbers+model used from Ra05 and that they have been rounded, and that the exact numbers are in the sidebar. Iridia (talk) 05:39, 4 February 2009 (UTC)

Kozai effect

I have noticed there is no ref to the Kozai effect. I tried searching it for a very long time, but this mechanism seems never to be connected with Haumea or 2003 EL61. Instead, I found a a document saying that Kozai resonant TNOs are found inside the 3:2, 5:3, 7:4 and 2:1 resonances, which is not the case of Haumea. May I ask, can any ref be provided? Thank you very much again. Jan.Kamenicek (talk) 20:45, 9 February 2009 (UTC)

Reference 23 in the Orbit section is the pertinent one for the whole sentence. Do you mean that this part should have greater detail? Iridia (talk) 22:47, 9 February 2009 (UTC)

Ok, I added a few more. Iridia (talk) 23:58, 9 February 2009 (UTC)

I had a look at both of the refs. However, both studies were published long before the Haumea's discovery. Can you quote the part from which you judge that it was Kozai mechanism that shifted Haumea away from the other members of its family? Thank you. Jan.Kamenicek (talk) 01:06, 10 February 2009 (UTC)

Ah, right - and thanks, going back and looking again let me find the problem that was making the paragraph confusing (paragraph now fixed). The first reference is to the Nature Letter by Brown et al. (2007):

"Long-term integration of the orbit of 2003 EL61 shows, however, that this object (and only this object) has large excursions in eccentricity over time owing to chaotic diffusion within the 12:7 mean-motion resonance with Neptune 11,12. We thus suggest that 2003 EL61 was initially part of the extremely tightly clustered group of objects and that the initial collision placed it within the nearby 12:7 resonance, which subsequently raised the eccentricity to its current value."

The next phrase is referenced to the two papers that are cited by Brown et al. (as 11,12) for the mechanism in orbital dynamics that raises eccentricity. Iridia (talk) 05:08, 10 February 2009 (UTC)

I see, now I understand. Thank you very much again. Jan.Kamenicek (talk) 08:22, 10 February 2009 (UTC)

Main page

I'd like to feature this article on the main page using File:2003 EL61.jpg, but it's fair use. Could someone please contact Michael Brown (mbrown@caltech.edu) and ask about getting a license for it? Raul654 (talk) 18:22, 4 May 2009 (UTC)

I don't think he can do anything about it. He doesn't own the copyright, the Keck Observatory does. You can ask them, but I think you'll just get the cold shoulder. Copyright's a touchy subject these days. Serendious 18:26, 4 May 2009 (UTC)

Well, I don't have a horse in this race. If someone wants to ask them, I'm all for it, but I'm too busy IRL to do it myself. Raul654 (talk) 20:00, 4 May 2009 (UTC)

Featured article

I don't know/can't remember what I did in the early stages to get this page in my watchlist, but on behalf of everyone like me who must have moved one full stop or corrected one spelling, well done on featured article status! doktorb _words 05:40, 6 May 2009 (UTC)

Discovery Credit

FYI: Mike Brown's collaborator, David Rabinowitz, submitted the name Haumea and it was approved as the name by the IAU. By convention, that makes Brown et al. the official discoverers of the object. Isentropiclift (talk) 15:15, 6 May 2009 (UTC)

Well, the UTC explicitly states that the discoverer was the Sierra Nevada Observatory. This is the kind of political FOSS the Spanish team has been subjected to.

Why Mike Brown did not report the finding to the MPC? Even a 12 year astronomy aficionado knows that you either report a finding to the IAU or you are not the discoverer. — Preceding unsigned comment added by 77.230.232.22 (talk) 18:56, 16 July 2011 (UTC)

Discovery date

Very nice article about Haumea and friends. One topic for consideration that I would like to bring up is the "discovery date." It is listed as 2004 for Brown et al. (that's me) and 2005 for Ortiz et al. In both cases, though, the date mentioned is simply the time that the images were taken, not the time that the discovery was made. Ours was Dec 28th 2004. Ortiz et al. claim that theirs was sometime in July 2005, though I don't know the precise date. It seems only a minor point, but I think it is important to make it clear that in 2003 and most of 2004 no one knew that this thing existed. Discovery only happens when someone knows. -- Mike Brown —Preceding unsigned comment added by Mebcit (talk • contribs) 20:20, 6 May 2009 (UTC)

Thanks, Mike. That's a problem with a lot of DP and SSSB articles. Often the only referenceable "discovery" date that we can find is the date of the image. Often it's not at all clear what the published dates refer to, so it's good to have clarification. kwami (talk) 06:39, 7 May 2009 (UTC)

If the IAU ruling is taken for the name of the dwarf planet, the same source should be used for discovery date and discoverer. So far the IAU stated that the discoverer was the Sierra Nevada Observatory and the discovery date March 7th, 2003. — Preceding unsigned comment added by 77.230.232.22 (talk) 18:59, 16 July 2011 (UTC)

tension vs compression

...its ellipsoidal shape is thought to result from its rapid rotation, and not from a lack of sufficient gravity to overcome the tensile strength of its material.

Shouldn't that be compressile strength (if ile is the right suffix)? Mountains aren't held up by tension. —Tamfang (talk) 04:02, 7 May 2009 (UTC)

Yup. "Compressive", actually. Good catch. kwami (talk) 06:48, 7 May 2009 (UTC)

Jarring incongruity

The mass coupled with the estimated size suggests a density of only ~0.5g/cm³. The mass coupled with the estimated density suggest a size of only ~720km (or, using similar triaxes ratios, 980km x 760km x 500km). Since these are glaringly out of sync (particularly obvious to a reader comparing against Pluto), it would help to note the incongruity and possible reasons for it, if anything has been published on the matter. Thanks. Strebe (talk) 22:44, 22 June 2009 (UTC)

I'm a little puzzled: I think what has happened is that in your calculations you have used the diameter, the measurements given in the article, as the radius, which is why your density is too low. Back of the envelope using the geometric mean diameter of 1.436x10^6 km gives me rho = (4 x 10^24 g)/(4/3*pi*(1.436 x 10^6 m /2)^3) = 2.6 g/cm^3, which is as expected, but about 0.3 g/cm^3 if there's no divide by 2 on the diameter. Iridia (talk) 03:33, 23 June 2009 (UTC)

Ah. Quite so. Apologies for the confusion. All the planetary info boxes give radius, even Eris and Makemake. Haumea and Orcus state diameters... which, besides deviating from the others, seems particularly odd for a triaxial ellipsoid in Haumea's case. I see that the articles on Sedna, Quaoar, and Varuna do not even state the metric; presumably "dimensions" in isolation means "diameter"? Strebe (talk) 10:19, 23 June 2009 (UTC)

Yes, it's a quirk of the field of TNO studies and its literature. These objects are so small compared to Earth-mass or Jovian-mass objects that it's easier to talk about their "size", given that for almost all cases they can't be resolved and their dimensions are calculated from their magnitudes in different colours and an assumed albedo, so the sizes have quite high uncertainties: +/- hundreds of km in most cases. It ends up with "size ranges" and "size distributions", with things not tied down to very precise numbers the way that they are for inner solar system objects or spacecraft-measured outer moons. Thanks for spotting that this hasn't been adequately documented here. Iridia (talk) 00:08, 24 June 2009 (UTC)

Issues with discovery section

I've given the discovery section a cleanup, but there were a number of uncited sentences, and a number of sentences I couldn't copyedit because I had no idea what they meant.

Later on July 27, 2005 new observations from the Observatorio Astronomico de Mallorca where submited. Submitted by whom? To whom?

By Ortiz & al. to the MPC. kwami (talk)

These logs were also used for subsequent observations, given that Ortiz have just scheduled telescope time at the Observatorio Astronomico de Mallorca to obtain confirmation images for a second announcement to the MPC on July 29 with additional precovery information. How does Ortiz scheduling telescope time at a Mallorca observatory imply that he used the Caltech team's logs? Serendious 06:54, 16 September 2009 (UTC)

They accessed the Caltec logs, then made their first announcement, then reaccessed the logs, then scheduled the telescope for confirmatory observations. Brown suspects that they needed more detailed data from him in order to properly aim the telescope to capture their images. kwami (talk) 07:02, 16 September 2009 (UTC)

Are there any sources for any of this? Serendious 20:15, 16 September 2009 (UTC)

Time of aphelion passage

Hello. The article says that Haumea passed aphelion in early 1992 and the given source is Horizons Web Interface, but I failed to find it there. Can you tell me, where it is written there, please? Thank you very much. Jan.Kamenicek (talk) 21:14, 1 January 2010 (UTC)

To find the aphelion date:
1. Load Horizons
2. Make sure Ephemeris Type shows the default of "OBSERVER".
3. Change "Observer Location" to: @sun (You are now at the center of the sun)
4. Change "Time Span" to 1990-01-01 to 1994-01-01
5. Click "Generate Empemeris"

When you see a deldot of zero, the object is changing relative direction. (A positive "deldot" means the target center is moving away from the observer (coordinate center=sun). A negative "deldot" means the target center is moving toward the observer.) The aphelion date for Haumea is estimated to have been about 1992-Jan-02. This date will slightly change as the orbit is further refined -- Kheider (talk) 21:47, 1 January 2010 (UTC)

I see. Thank you very much. Jan.Kamenicek (talk) 22:40, 1 January 2010 (UTC)

Contact

wonderfull puzzle. however reading through the article a few times i thought we are having a (near) contact binary here, just an impression so i dont have an obvious clue to why i think that (it just looks like it could be one). yet this water ice is suggestive . i wonder would a (near) contact binary be able to induce enough tidal heat to smelt the ice on Haumea's scale? -- 24.132.171.225 (talk) 13:06, 8 March 2010 (UTC)

At that range (near-contact) the two bodies would be tidally locked. If it was a contact binary, the smaller size of the two bodies would probably (IMHO) be low enough that the tidal forces would be well balanced and non-varying across the two bodies. This is actually (again IMHO) the most exciting reason for going to Pluto. Is Pluto less or more active than Triton? -- Kheider (talk) 16:06, 8 March 2010 (UTC)

Rotation

"rotation ... 3.9 hours ... indeed faster than any other known body larger than 100 km in diameter"

1. 20000 Varuna is listed to have diameter 500+ km and rotation period possibly 3.17 hours (or 6.34 hours). —Preceding unsigned comment added by MistySpock (talk • contribs) 15:04, 25 May 2010 (UTC)

Classification

Currently Haumea has observations over 55.2 years and is clearly not in the 12:7 resonance. See http://www.boulder.swri.edu/~buie/kbo/astrom/136108.html This bit needs clearing up (and perhaps anything else based on nominal orbits). The libration plot should also go. Andrew W. 115.128.25.119 (talk) 11:02, 2 July 2010 (UTC)

I am not so certain. 55 years of a 281 year orbit means that it has only been observed over ~20% of its complete arc. To be in the fifth-order resonance it would have to have a specific orbit and the DES simulation "±3 sigma" may jump from one side of the resonance to the other side of the resonance. I should also point out that the Buie/DES automatic program does not handle many high-order resonances. At Misplaced Pages we need to try to avoid potential OR, especially when dealing with FAs. Mike Brown's 2007 paper says, "2003 EL61 is in the fifth-order 12:7 resonance". We would need a reliable reference, preferably integrated over a 100+Myr (the DES is a mere 10Myr), to clearly state otherwise. -- Kheider (talk) 17:48, 2 July 2010 (UTC)

Um...the earliest year associated with the discovery of Haumea in this article is 2003. You posted your comment in 2010. 2010-2003=7 years. Where is the 55.2 years of observations coming from? Do you have info regarding precovery photographs dating back to 1955? If so, could you cite a reliable source and add them to this article? Wabbott9 (talk) 17:39, 18 December 2010 (UTC)

See the first link of this section, to SWRI. There are precovery images going back to 1955. Tbayboy (talk) 19:33, 18 December 2010 (UTC)

If you look at DES/Buie and JPL you will see that the first observation (precovery image) is 1955 03 22.22223 UT. (Giving us 55.23 years worth of data). The precovery image comes from the Palomar Mountain Digitized Sky Survey (observatory code #261). You might find Precovery#Dwarf_planets interesting.-- Kheider (talk) 19:38, 18 December 2010 (UTC)

Unique elongation

The header claims that "Haumea's extreme elongation makes it unique among known" TNOs. However, the article on (20000) Varuna says that Varuna is elongated, too. So Haumea's is not "unique", but just "rare" or "unusual". Except, maybe the claim for uniquity is based upon the uncertainty of the Varuna claim? Even so, I think the "unique" claim is overstated, since it is still plausible for Varuna. Tbayboy (talk) 17:15, 19 July 2010 (UTC)

It would be unique (and extreme) among known dwarf planets and that does basically include TNOs with known diameters. But yes, it is somewhat misleading since a typical mid-sized TNO should be irregular in shape. We could change it to say "among known dwarf planets". I believe the status of Varuna (since Varuna is around 500km in diameter and thus half the size of Haumea) is that it is suspected of being elongated, but unconfirmed. -- Kheider (talk) 17:34, 19 July 2010 (UTC)

See the Varuna page. The IR size measurements are 500 (Spitzer) and ~900 (two others, earlier), but the Spitzer authors had problems and prefer the earlier results, so it's a solid DP candidate. As to elongation, both are assumed elongated because of their apparent spin, neither confirmed. All of which is to say that it's a fine distinction to make here re "known". It definitely should say "dwarf planet" or "plutoid" or "objects in hydrostatic equilibrium", just to exclude potatoes (wasn't a little TNO recently measured by occultation?). I don't see any reason to emphasise the rarity of elongation as compared to other TNOs, though, since it applies to all known HE bodies, including planets and stars! Tbayboy (talk) 18:56, 19 July 2010 (UTC)

2002 TX300 occultation results were just released and 28978 Ixion may have occulted a star last night. -- Kheider (talk) 19:39, 19 July 2010 (UTC)

'Very early' collision for the Haumea family?

The last sentence's conclusion doesn't seem to follow, logically.

"Because it would have taken at least a billion years for the group to have diffused as far as it has, the collision which created the Haumea family is believed to have occurred very early in the Solar System's history."

If the Solar System is ~4.5 billion years old, why does the diffusion requiring 1 billion years require a collision 'very early' in its history? Surely any time on the first 3/4 of of its lifespan would do?

Also, perhaps it would be rephrased so the sentence doesn't start with 'Because'. —Preceding unsigned comment added by 81.156.125.41 (talk) 13:52, 18 August 2010 (UTC)

Crystalline ice covers 75% of Haumea surface

• "Dwarf planet Haumea shines with crystalline ice". Physorg.com. May 12, 2011. Retrieved 2011-05-12.
• Dumas, C.; Carry, B.; Hestroffer, D.; Merlin, F. (2011). "High-contrast observations of (136108) Haumea. A crystalline water-ice multiple system". Astronomy & Astrophysics. 528. Bibcode:2011A&A...528A.105D. doi:10.1051/0004-6361/201015011. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

Regards, RJH (talk) 21:28, 12 May 2011 (UTC)

Uncertainty in Absolute Magnitude

Why there is such a big uncertainty in the absolute magnitude? --JorisvS (talk) 12:05, 19 August 2011 (UTC)

In the source (JPL), it's similar to that of several other big TNOs I looked at. It just seems to be the accuracy of the current technology. Tbayboy (talk) 14:24, 19 August 2011 (UTC)

Scalene

Why is Haumea a scalene ellipsoid and not an oblate one? --JorisvS (talk) 10:12, 6 December 2011 (UTC)

Rapid spinning. Spin a little and it flattens out, like Saturn. Spin more, and it starts to break apart, stretching out the oblate object into a scalene. There's a paper referenced in (IIRC) a recent Distant EKOs that suggests that many of the TNO multiples are caused by spin-induced fissioning, not huge impacts. Per the paper, the spin can be caused by several smaller (non-catastrophic) impacts. Once it spins fast enough, it stretches into a rugby ball like shape, and material can fly off the tips, forming moons. Tbayboy (talk) 18:08, 6 December 2011 (UTC)

So why would it become scalene when spinning rapidly enough? Something needs to break rotational symmetry for this to happen. Is the little gravity from perturbing bodies sufficient to do this? --JorisvS (talk) 18:54, 6 December 2011 (UTC)

This would usually be before any satellites (the paper's hypothesis is that it is the cause of the satellites), but I would guess any pre-existing satellites could have such an influence. My guess is simply that the final push to "too much spin" is caused by a collision, which itself provides asymmetry in mass and energy. Even without considering that, the body itself would not be perfectly symmetric. Tbayboy (talk) 19:22, 6 December 2011 (UTC)

Instability in the body itself would be enough. No body is perfectly uniform. We could theoretically have an oblate body past the scalene limit, if it were perfectly uniform, just as we can have liquid water below its freezing point, but it would be unstable. — kwami (talk) 19:38, 6 December 2011 (UTC)

Yes, makes sense. Could we add something about this to the article? At which rotation period would a rotating body turn into a scalene ellipsoid? --JorisvS (talk) 19:43, 6 December 2011 (UTC)

I'll try to re-find the paper tonight and put a link here. I'm unsure of the applicability, since it's a new, unchallenged hypothesis, and I'm not sure of competing hypotheses (one big smack? merged contact binary?). No idea on your second question. I think that would depend on a lot of factors. Note that one of the examples I read (somewhere) of oblate-to-scalene transformation is hand-spinning pizza dough, so the concept covers a lot of territory. Tbayboy (talk) 20:13, 6 December 2011 (UTC)

It was easy to find: Rotational fission of Trans-Neptunian Objects. The case of Haumea Tbayboy (talk) 21:49, 6 December 2011 (UTC)

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dubious tag

I've tagged the claim that Haumea and Makemake are DPs as 'dubious' not there because I doubt they are—I don't,—but because the wording is inconsistent with other articles and reflects bias for some sources over other, perfectly good ones (Sheppard, Brown, Tancredi, etc.). I'd be happy with using "is" only for the 3 known DPs, or for the 9 "must be" DPs, but not for a distinction based on H when H is not part of the IAU definition of a DP. (Perhaps some sort of 'bias' tag would be better than 'dubious'? If so, I'll be happy to change it.)

My suggested wording is,

It has been accepted as a dwarf planet for naming purposes by the International Astronomical Union and by most astronomers.

As far as I can tell from all the sources we have, those are the facts: Haumea and Makemake are not actually known to be DPs, unlike Ceres, Pluto, and Eris, which per Tancredi are directly confirmable, and which the most skeptical of our sources, Sheppard, accepts without reservation. The only sourceable (as opposed to OR) distinction between them and the Brown four is that Haumea and Makemake have been accepted as DPs by the IAU and therefore by the great majority of astronomers. (I say OR, because it is not up to us to set a lower mass, size, or precision boundary for DPs as a way of separating Haumea and Makemake from the Brown four.) If my wording does not adequately reflect the sources, then I'm sure someone can come up with better. — kwami (talk) 11:02, 6 January 2012 (UTC)

As for your reference "Plutoid chosen as name for Solar System objects like Pluto", it states it very clearly that these "very bright absmag<1" objects are listed as dwarf planets. It then states they will be removed "If further investigations show that the object is not massive enough". We have no references that Makemake is not massive enough and we KNOW the mass of Haumea. -- Kheider (talk) 13:04, 6 January 2012 (UTC)

Yes, it does state that very clearly, which is why we should reflect it in the lead, and why I'm so puzzled by your continuing refusal to do so.

The essential point is hydrostatic equilibrium. That is what the IAU definition is based on. "Massive enough" means "massive enough to cause HE". The fact that we know the mass of Haumea is not the issue, as the HE limit depends on factors besides mass (such as tensile strength), and it has not been established. Also, we don't know the mass of Makemake (as you just pointed out in the lead), but that makes no difference to IAU naming, which is not based on HE, but on abs. magnitude. The IAU is acknowledging here that just naming a body through DP channels does not make it a DP. Accepting it as a DP does not make it a DP. What makes it a DP is whether it's in HE, and we don't know that, as the IAU itself admits.

Everyone (AFAIK) accepts that Ceres, Pluto, and Eris are in HE, so there is no debate about them being DPs. (The only debate is whether DPs should be considered planets, as Stern maintains, but that's a philosophical difference, not a factual one.) Not everyone accepts that Haumea and Makemake are in HE, so there is debate, and brushing it under the carpet is an embarrassment to WP. Granted, there isn't very much debate: The IAU makes allowances for the possibility, but most sources simply accept them as DPs. However, the IAU did not accept them as DPs because it's been demonstrated that they are DPs, but because they set up a criterion for which committee got to name them. An arbitrary criterion, which had only the most tenuous connection to the definition of a DP. Sheppard reflects this by saying they are "likely" to be DPs, the same wording he uses for Sedna, OR10, Quaoar, and Orcus. That's the issue that we should be honest enough to address up front: not that they "are" DPs, but that they have been accepted as DPs by the IAU and most everyone else. Either that, or we can say that all of Sheppard's list "are" DPs: Neither Sheppard, nor Brown, nor Tancredi draw a line at H < 1. Either way works for me, just as long as we're consistent. — kwami (talk) 14:11, 6 January 2012 (UTC)

You can not live a day without lying. No source says that "Haumea" was accepted for naming purposes". Ruslik_Zero 14:22, 6 January 2012 (UTC)

Are you really so arrogant that you think that anyone who disagrees with you is "lying"? — kwami (talk) 14:46, 6 January 2012 (UTC)

Ruslik, read the IAU release linked to above by Kheider, specifically the paragraph beginning with "In Oslo, members ...". --JorisvS (talk) 14:48, 6 January 2012 (UTC)

I have read it many times. However I have been unable to find where it says anything about Makemake or Haumea. Ruslik_Zero 14:51, 6 January 2012 (UTC)

Please keep YOUR definition of a dwarf planet to the Talk:Dwarf planet page where the consensus is that we list the 5 IAU dwarfs and the rest as merely strong candidates. Any object with an abs mag < 1 will be a dwarf-planet beyond any reasonable doubt because it will be almost impossible for such a body to be less than 800 km in diameter. The data showing Sedna and OR10 as dps is not as solid as the data showing Haumea (bright+known mass) and Makemake (bright+size fairly well measured @ 1400km). -- Kheider (talk) 14:52, 6 January 2012 (UTC)

Is that my definition? Funny, I don't remember draughting it for the IAU. They didn't even give me credit for it!

The IAU has chosen one arbitrary boundary as safe. Brown has chosen another. Sheppard yet another. They disagree with each other. Where sources disagree, it is our responsibility to report on the disagreement. It is irresponsible to cherry-pick references to get the result we favor. And, of course, your opinion on the DP page is not "consensus". — kwami (talk) 15:01, 6 January 2012 (UTC)

The IAU 5 is the logical mid-point between only 3 dwarfs and claiming 9+. All the sources are in basic agreement over the 5 IAU dwarfs. -- Kheider (talk) 15:13, 6 January 2012 (UTC)

That is not true. Sheppard et al. (2011) talk about Haumea and Makemake as 'likely dwarf planets', on a par with Sedna, 2007 OR10, Orcus, and Quaoar. --JorisvS (talk) 15:17, 6 January 2012 (UTC)

(edit conflict) Not logical, just in-between. All of these populations—3, 5, 9, and the others—are reasonable, but all are arbitrary. (Apart from Sheppard's 3, which are the only ones actually demonstrated to be in HE.) If we're to be honest to the scientific literature, which we have an obligation to be, then we need to report the Sheppard 3, the IAU 5, and the Brown 9. — kwami (talk) 15:22, 6 January 2012 (UTC)

Sheppard (2011) page 7 says, "as are the next largest bodies in the outer solar system such as Sedna, 2007 OR10, Orcus and Quaoar." This (IMHO) suggests Sheppard treat these 4 as lesser than the Haumea and Makemake. Obviously they are lesser candidates (Sedna, OR10) or smaller (Orcus, Quaoar) based on what I outlined above: "The data showing Sedna and OR10 as dps is not as solid as the data showing Haumea (bright+known mass) and Makemake (bright+size fairly well measured @ 1400km)." -- Kheider (talk) 15:33, 6 January 2012 (UTC)

But that is OR. You are reading a personal interpretation into his words. What I read into them is that he's listing the 'official' DPs first, because they are official and therefore usually presented separately. What he actually says of all six is that they are "likely", so that's all we can take away from it.

I do agree, of course, that the data isn't as solid for the Brown four. But the point is that, apart from the original three, the data isn't solid for any of them. We're dealing with degrees of solidity, and varying opinions as to where we should draw the line. Sheppard accepts none, the IAU two, Brown six, but these are all opinions, not facts, and we need to report the opinions of experts in the field when they differ.

I also appreciate your account above of the IAU rational, and would be happy to accept s.t. along those lines as superior to my wording of "accepted for naming purposes", which doesn't capture the essence of the IAU decision. — kwami (talk) 15:42, 6 January 2012 (UTC)

(edit conflict)Yet, he considers Makemake and Haumea 'likely DPs', just like Sedna etc., which he contrasts with 'bonafide DPs' Eris, Pluto, and Ceres. --JorisvS (talk) 15:43, 6 January 2012 (UTC)

BTW, Kheider, it's been a long time since I felt we were having a constructive discussion. It's nice. — kwami (talk) 15:49, 6 January 2012 (UTC)

I agree that Sheppard (nor Brown, nor Kevin Heider) are 100% certain that Haumea or Makemake are dps, but to treat them on the same level as Sedna and OR10 (which have undetermined sizes and masses) would be misleading. -- Kheider (talk) 15:53, 6 January 2012 (UTC)

But I've never said we should treat them on the same level! 3 are universally accepted. They "are" DPs by any referenceable standard. 2 are accepted by the IAU for the reasons you gave above. Due to the importance of the IAU, they are generally accepted as DPs, and of course the circumstantial evidence is stronger than for the rest. 4 more are accepted by Sheppard and Brown as being on par with these two. Sheppard uses the word "likely", and Brown "virtually certain" and "must be". Tancredi & Favre would add a few more, but we haven't heard from them for a few years. I'm not asking that we follow Brown or Sheppard instead of the IAU, just that we not follow the IAU to the exclusion of Brown & Sheppard. When we describe an object as a DP or likely DP, that initial claim should reflect the literature. The exact wording isn't so important, as long as we do not privilege our favoured source over the others. — kwami (talk) 16:08, 6 January 2012 (UTC)

"4 more are accepted by Sheppard and Brown as being on par with the these two." (Haumea+Makemake) This is the part I feel is synthesis. -- Kheider (talk) 16:17, 6 January 2012 (UTC)

Where's the synthesis? They use the same words to describe the likelihood of them being DPs. That's what we have to go on. For Sheppard, 3 are "bonafide", 6 are "likely". For Brown, all nine "must be" DPs. In Tancredi & Favre, all but OR10 (which is too recent) are marked "yes" under the DP column. I don't see any synth there. Their criteria merely differ from the IAU's. — kwami (talk) 16:29, 6 January 2012 (UTC)

Neither Sheppard nor Brown specifically state that "Sedna, 2007 OR10, Orcus, and Quaoar" are just as likely to be dps as are Haumea and Makemake. -- Kheider (talk) 16:46, 6 January 2012 (UTC)

And I don't expect that they do think that. (Also, the IAU doesn't specifically state that H and M are just as likely to be DPs as C, Pl, & E.) But that's irrelevant, because no-one claims they do, and nothing depends on them doing so. The point is that different sources have different criteria for which bodies they accept as DPs. Sheppard accepts 3. The IAU accepts 5. Brown accepts 9. Tancredi accepts 12. You've chosen one number out of several, and defended it essentially with an argument from authority. That's legit when defining what a DP is, because no-one disputes the IAU definition or their role in establishing it, but scientific claims cannot be established that way. Doing so is profoundly unscientific. — kwami (talk) 17:26, 6 January 2012 (UTC)

In the Haumea and Makemake articles, NONE of the sources (EDIT: currently in use in the article) suggest that they (EDIT: Haumea and Makemake) are not (EDIT: likely to be) dps. The whole Talk:Dwarf planet issue about inserting table(s) listing many poorly known candidates (objects with unknown masses and sizes likely less than 1400km) is subject for that article, not Haumea or Makemake. -- Kheider (talk)

That makes no sense at all. We can only say things that are supported by the sources already in the article? So if Sedna were declared a DP by the IAU tomorrow, we wouldn't be able to mention that in the Sedna article, because none of the existing sources say it?

Kheider, we follow sources. That's all this has ever been about. After a few hopeful hours of reasonable discussion, you would appear to be reverting to "I don't like it". — kwami (talk) 18:38, 6 January 2012 (UTC)

If we had an IAU reference stating that the IAU declared Sedna a dp, we would change the Sedna article to reflect an increased consensus. Hopefully the IAU would give an explanation (since as of today we do not know the mass or size of Sedna.) Misplaced Pages is not a crystal ball and I do not think we should clutter the dwarf planet article with needless tables about the lesser candidates that do not add to the understanding of the topic. We already have two sections in the dwarf planet article called "Official and "nearly certain" dwarf planets and Additional candidates -- Kheider (talk) 18:54, 6 January 2012 (UTC)

What are you talking about? No-one is advocating that either! Honestly, I don't know where you get these ideas.

At DP, I'm asking that we consolidate the tables, because the current division is SYNTH, and the headers contradict our sources. You said you would find it acceptable if we had one table coded by who accepted the body as a DP. No-one is saying that we should add more tables.

If we could add more IAU sources to the Sedna article, then why would you object to adding sources to this article? I don't get it. If we have a RS that Haumea is or maybe is or maybe is not a DP, why shouldn't we be able to add it? — kwami (talk) 19:01, 6 January 2012 (UTC)

Ok, back to Haumea/Makemake, show me one source that states Haumea/Makemake are NOT likely to be dps. We already know the IAU does not currently list Sedna or OR10 as a dps. -- Kheider (talk) 19:13, 6 January 2012 (UTC)

Again, where are you coming from? No-one has ever said that Haumea or Makemake are not likely to be DPs. And of course the IAU does not list Sedna. No-one ever said that either. — kwami (talk) 19:32, 6 January 2012 (UTC)

You added the dubious tag to this article to help restart the never-ending Talk:Dwarf planet debate. This all started in August 2011 when you decided to list Sedna, OR10, Orcus, and Quaoar as dwarf planets. Your POV-pushing pushed a lot of buttons when you should have been busier getting a consensus on the talk page. I am still not convinced a combined IAU dp+candidates table adds anything to the article, or if it just makes it more difficult for the average reader. Some of your early synthesis was that even Eris was not accepted as a dp. -- Kheider (talk) 19:47, 6 January 2012 (UTC)-- Kheider (talk) 19:47, 6 January 2012 (UTC)

Again, you're misrepresenting me. I never said that Eris was not a DP, and certainly don't say that in the link you just gave.

At the time of that edit, we had been discussing sources which said that Ceres and Pluto are known to be in HE through direct measurement, and that Eris is assumed to be in HE because it is more massive than Pluto. With the sources we're now discussing, however, there is no such distinction: Tancredi says that all three are known through direct measurement, and Sheppard says that all three are "bona fide". That was new to me, but all I'm asking is that we respect our sources, and I'm happy to accept all three as certain if that's what our sources say.

I chose the 'dubious' tag because it was the best in-line tag I knew of. A 'POV' tag would have marked the entire article, and I didn't want to do that. I did offer to switch the tag if s.o. knew of a more appropriate one.

As for POV-pushing, the POV I'm pushing is that of the sources. We should reflect all of them, not just one which WP elevates above the rest, as if we were some sort of scientific arbiter.

And as for pushing buttons, are we really going to purposefully not do a good job on the article just because we don't like the attitude of another editor? Isn't that just being WP:pointy? — kwami (talk) 20:06, 6 January 2012 (UTC)

My objection to the lead as it stands now: in the beginning of the first paragraph, we state that it "is" a DP. At the end, we report that a RS says it is "likely" to be a DP. That is logically inconsistent. — kwami (talk) 10:51, 7 January 2012 (UTC)

• My response copied from the RSN discussion,

"If there is a dispute between the IAU and other experts in the field, then you cannot say de facto that anything is something. You have you say that the IAU considers this to be a DP and these other experts consider it to likely be a DP. An short explanation of the different standards that these experts are using may also be required for clarification in the article. But if there is a dispute between experts in the field (and the IAU count as experts, but experts alone and shouldn't be held as definitive on the subject. Our readers must place their own emphasis on which opinion holds better weight, we as editors may not), then you must adequately show both sides of the dispute without being biased toward one side or the other." Silverseren 11:07, 7 January 2012 (UTC)

This is an artificially manufactured controversy. The volume of literature where Haumea is ambiguously identified as a dwarf planet significantly exceed anything that Kwamikagami has been able to did up so far. You can see yourself. Even in the Sheppard's article cited above "Haumea" is said to be "likely" in just one throw-away sentence with unclear meaning. Scott Sheppard has never disputed that Haumea is a dwarf planet. For instance, in this article, where he is a coauthor, Haumea is called a dwarf planet without any qualification. So, in even in the worst case the position of Scott Sheppard is unclear. So, summarizing: this is a non-existent controversy, which User:Kwamikagami tries to create by selectively citing some papers out of context. Ruslik_Zero 13:56, 7 January 2012 (UTC)

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