Talk:Haumea/Archive 2

Archive 1

Archive 2

Archive 3

Understanding of the shape

It is, from my point of view, a bit unclear what causes this elongation. From my basic understanding of rotating gas bodies (e.g. giant planets or stars) a rapid rotation would cause an strong flattening of the spheroid shape, however, with still a rotational symmetry. Elongations that distrupt this symmetry can, as far as I know, only occur in near-contact binary stars. A triaxial ellipsoid does not have a rotational symmetry, and, according to Mike Brown's animation (see his homepage) Haumea probably rotates around one of its shorter axes. Can this elongation still be explained by a combined action of rotation and gravity (i.e. could you produce such a shape with a liquid instead a solid material), or is it just a special case of a highly deformed body that, however, is still marginally gravitationally bound (with gravity being stronger than the material strength)? If the absence of a rotational symmetry is due to (semi-)rigid properties than this would challenge Haumea's classification of a dwarf planet (hydrostatic equilibrium).--SiriusB (talk) 09:55, 24 September 2008 (UTC)

That's a more detailed version of what I said in #I think this article should make clear. Remember "hydrostatic" is from hudor, water. Peter jackson (talk) 10:34, 24 September 2008 (UTC)

I seriously doubt Brown would have gotten confused about hydro. eq. I'll see if I can find any refs. kwami (talk) 17:16, 24 September 2008 (UTC)

Can this wait? There still are more important issues to resolve, like tracking down missing citations. Serendi^podous 17:41, 24 September 2008 (UTC)

Lots of talk about rotational ellipsoids (spheroids). Nothing yet about them destabilizing into scalene ellipsoids at high angular velocities. kwami (talk) 18:53, 24 September 2008 (UTC)

I've found refs to Chandrasekhar (1987) speaking of Jacobi ellipsoids, but haven't gotten access to the original. Tancredi, e.g., has a PPT showing a Jacobi triaxial ellipsoid in fast rotation and refs Chandrasekhar. However, I have found a summary from 1909, in "The ellipsoidal figures of equilibrium of rotating homogeneous fluids":

Jacobi has shown that if ω²/2πk²σ < 0.18709 ... there is an ellipsoid of three unequal axes satisfying the conditions for equilibrium. When this quantity is very small, the axis of rotation and one other are very short and nearly equal to each other, while the third is relatively very long. With greater values of this quantity the shorter axes are longer and the longest axis is shorter.

(at the limit 0.18709... the figure becomes a spheroid.) kwami (talk) 20:12, 24 September 2008 (UTC)

Wow, speed it up enough, and it's no longer even ellipsoidal anymore: it's pirriform! [1] kwami (talk) 20:23, 24 September 2008 (UTC)

Is it a stable equilibrium? Peter jackson (talk) 11:12, 29 September 2008 (UTC)

Yes, it has to be. Unless the angular velocity changes, of course. kwami (talk) 11:25, 29 September 2008 (UTC)

SolStation

The two uncited facts in "Discovery Controversy" were most likely taken from SolStation's article on Haumea. I've emailed SolStation to ask for their sources but haven't heard back. I don't know where SolStation falls on Wikipedia's vicious scale of noteworthiness, but it has been used as a source in other articles. So can we use it? Serendi^podous 12:49, 25 September 2008 (UTC)

I think that's Brown's take on what happened. I think the precovery date is verifiable, but I haven't seen Ortiz giving the discovery date. It would be nice if we had copies of the Ortiz email. kwami (talk) 14:48, 25 September 2008 (UTC)

The date appears at http://www.infoastro.com/200809/26ataecina-haumea.html and it is 2003 Mar. 7 Sorry, I did not read the other parts of the discussion --NudoMarinero (Talk) 13:19, 28 September 2008 (UTC). --NudoMarinero (Talk) 12:52, 28 September 2008 (UTC)

Why are you looking for a different discovering date than the official one which is at IAU? (WP:NOR) --NudoMarinero (Talk) 13:19, 28 September 2008 (UTC)

Because we know from Sanz that that isn't actually the discovery date. AFAIK, at least from Brown et al., the discovery date is the date you discover the object. It isn't the date of the image you discover it on. If, for example, Sanz had discovered Haumea on that Palomar slide, the discovery date would presumably not be given as 1955! kwami (talk) 17:57, 28 September 2008 (UTC)

classification

what about being a cubewano? Nergaal (talk) 22:23, 25 September 2008 (UTC)

What about it? It was already classified as such, and you just added more prose to that effect, so I don't understand the question. kwami (talk) 23:19, 25 September 2008 (UTC)

in the classification section it is not stated that it is also a cubewano. it is said only later. btw, I added a few tags where I did not know how to expand, but I thought is needed. Nergaal (talk) 23:25, 25 September 2008 (UTC)

Actually, I agree with Nergaal. The classification section should explain what a classical KBO is. In fact nowhere in the article explains what a classical KBO is. It should be mentioned in the intro too. Serendi^podous 09:50, 26 September 2008 (UTC)

Done. Given that the exact definition of this population is agreed on by dynamicists, who like to use a three-point list of complicated dynamical properties, I thought it more important to mention the broader context of the population to the Kuiper belt than to explain every single detail. Iridia (talk) 02:16, 27 September 2008 (UTC)

controversy

I've rewritten the controversy section, to include Sanz' POV. Serendipodous, I know you've spent a lot of time ironing out the refs. I hope I didn't mess anything up.

I deleted the word "later" from the following:

Ortiz later admitted he accessed the internet logs a day before making his announcement, but denied any wrongdoing.

Did he at first deny that they accessed the logs? If so, we should state that directly; if not, the word "later" is misleading. kwami (talk) 07:51, 28 September 2008 (UTC)

Okay, I see where the "later" comes from, not from denial, but from initial silence. kwami (talk) 20:25, 28 September 2008 (UTC)

Suggestion: right now the controversy section is a bit on the huge side. I believe that moving all the information there into a separate article, and then trimming down unessential stuff might be better (i.e. how is the daughter issue worth being specified in this article?) Nergaal (talk) 21:32, 28 September 2008 (UTC)

I've reduced it a bit, but seriously, it needs way more trimming. Since this is a FAC-wannabe, it is probably not necessary to have more than twice, or three times the amount of information given in the introduction of the sub-article now. Nergaal (talk) 06:59, 29 September 2008 (UTC)

This is quite complicated; I really don't think we can trim it substantially without potentially confusing or misleading the reader. Truthfully, I don't think the sub-article is needed at present. Serendi^podous 07:50, 29 September 2008 (UTC)

This is something that will probably lose interest for people over time. In five years, will anyone really care, except as a point of trivia? However, I agree with Serendipodous that the results would probably be misleading if we, say, cut it in half. We'll probably need to reduce it to a paragraph that says little more than that there are two claimants; one thinks the other is a fraud, the other says the first is a bully, the IAU sidestepped the issue, and neither claimant is happy with the outcome. kwami (talk) 11:22, 29 September 2008 (UTC)

We might want to also remove some of the naming controversy to the secondary article. kwami (talk) 11:28, 29 September 2008 (UTC)

Done. But strangely Haumea's article is now as long as Makemake's despite having far more science to discuss. We may need to look at Makemake's article to see why. Serendi^podous 12:09, 29 September 2008 (UTC)

The lead & the box both assert as fct that it was discovered by Brown in 2004 & Ortiz in 2005. The IAU asserts as fact that it was discovered in Spain in 2003. What's happened to NPOV? Peter jackson (talk) 11:15, 29 September 2008 (UTC)

No one doubts that Brown was the first to discover it. But the Spain group got their application to the IAU first, which gives them technical credit. The 2003 date refers (I think) to the first time it was observed, not discovered. Serendi^podous 11:17, 29 September 2008 (UTC)

It was not discovered in 2003, unless "discovered" means the date of the plate you discovered it on. Serendipodous, that isn't the case, is it? I mean, if Sanz had found Haumea on that Palomar plate, would the discovery date be listed as 1955? kwami (talk) 11:22, 29 September 2008 (UTC)

I honestly don't know o_O But the object is nonetheless 2003 EL61. Serendi^podous 11:40, 29 September 2008 (UTC)

What about the automatically assigned computer code K40506A? That's what Sanz reports, but it would mean a discovery date by Brown of 2004-V-06, which is too early per Brown. kwami (talk) 11:59, 29 September 2008 (UTC)

It looks like the IAU assigns numbers according to the date of the discovery image was taken, not the date of discovery. Take a look at Eris. They also give this as the discovery date. Brown didn't discover Eris until after Haumea, but we give it an earlier discovery date. Since nearly all of our "discovery" dates come from the IAU, perhaps we should always give that but specify the actual date when we know it. kwami (talk) 12:19, 29 September 2008 (UTC)

At least that sounds like a consistent system.

As regards "precovery", remember Neptune was recorded by Galileo in 1612. Does the IAU or anyone else have a consistent definition of discovery? Uranus, Neptune &c are regarded as being discovered by those who realized they were planets. What about Earth then? Do we list it as discovered by Philolaus of Tarentum, the 1st to suggest it's a planet, or Johannes Kepler, who seems to me, applying modern standards of scientific proof retrospectively, to have been the 1st to prove it, in 1619? Either would look a bit odd. Peter jackson (talk) 10:49, 30 September 2008 (UTC)

For Earth & the original 7 "planets", people normally just say "prehistoric". That has nothing to do with this issue.

If "discovery dates" aren't discovery dates, then we're just lying to our readers. kwami (talk) 18:44, 30 September 2008 (UTC)

Exactly. Statements in infoboxes ought to be unequivocally true, unless they are clearly flagged. Since there isn't a concept of "discovery" that will be immediately obvious to the reader, the 1st possibility isn't actually a possibility. Peter jackson (talk) 10:47, 1 October 2008 (UTC)

I still think

That the information in this article is very important, but that the source is not really all that clear on the dynamics behind it. A better, preferably scholarly source, should be located and this information placed in the "orbit" section. Serendi^podous 14:14, 29 September 2008 (UTC)

Buie lists Haumea as SCATNEAR over a 10 Myr integration. If it was unstable on the time scale of 2 Myr I would think the DES would list it as a centaur. I do not know if I like listing it as a cubewano. The MPC use to list it as a cubewano, but no longer seems to. -- Kheider (talk) 18:17, 29 September 2008 (UTC)

Nope. Still does:

(136472) Makemake cubewano 103109 1 2008 May 22 B24 16.3 R

Serendi^podous 18:26, 29 September 2008 (UTC)

Makemake != 2003 EL61... -- Kheider (talk) 18:45, 29 September 2008 (UTC)

Oh yeah. Did I ever mention I'm a MENSA member? Strange. However, since it is named after a creation deity, it seems likely to have been at least nominally a cubewano. Serendi^podous 19:22, 29 September 2008 (UTC)

Cold orbits are assumed not to have been significantly altered by Neptune. In defining ‘‘Classical,’’ we are trying to determine those KBOs with orbits that have been relatively undisturbed since the origin of the solar system. -- Kheider (talk) 16:05, 2 October 2008 (UTC)

first circular

I cannot read into this report where is Haumea listed. I would prefer having this as a reference in the text. Nergaal (talk) 17:01, 29 September 2008 (UTC)

GAN?

Is this ready for GA? Nergaal (talk) 17:10, 29 September 2008 (UTC)

Still some citation tags. Serendi^podous 17:12, 29 September 2008 (UTC)

That's obvious, but besides that? Plus, there is usually a significant delay b/w the nom and the review, so if the article is nominated now, it still has a few days for touch-ups. Nergaal (talk) 17:47, 29 September 2008 (UTC)

I still can't figure out why Makemake (dwarf planet) is as long as this article when this article contains so much more science. I keep thinking that something fundamental must be wrong, either with this article, or with that one. Serendi^podous 17:49, 29 September 2008 (UTC)

The physical characteristics there is waay broader, and the discovery is less succinct. Nergaal (talk) 17:52, 29 September 2008 (UTC)

In that case I have no objections, provided the citation tags are fixed quickly. Serendi^podous 17:56, 29 September 2008 (UTC)

There are a couple other problems. The discovery date: It appears that Eris is also give the telescope observation date as its discovery date, which means we may have a broader problem here. K40506A: These Caltech codes are K followed by the date (YMMDD) followed by a A = 1st object of the day (see his Makemake blog 'what's in a name 2'). We need to iron this out. kwami (talk) 19:00, 29 September 2008 (UTC)

I'm still not clear on why this is an issue. The discovery dates seem perfectly fine to me. The IAU's official dates seem only useful for cataloging. Serendi^podous 19:25, 29 September 2008 (UTC)

If we're listing catalog dates as discovery dates for other TNOs, don't you think that's a problem? How do our readers know when the info box contains a catalog date, and when it's the actual discovery date? For example, K40506A records the date of Brown's discovery image of Haumea. Now K50331A is the code for Makemake, and matches the "discovery" date in our info box. I rather doubt they identified Makemake as a new TNO the same date the discovery image was taken. So what does the "Discovery date" field in our info box actually mean? kwami (talk) 22:06, 29 September 2008 (UTC)

As far as I can tell, the date given in the IAU designation is the earliest recorded observation at the time the discovery is submitted to the IAU. Thus it ignores the actual date of discovery and and future earlier recorded observations that may be found. It is therefore quite arbitrary and means nothing. Serendi^podous 07:39, 30 September 2008 (UTC)

So we have hundreds of SSSB articles with spurious data in them. Great. Guess it doesn't matter in the early days, since people rushed to get their discoveries recorded and didn't have precoveries. And for many minor bodies in makes no practical difference, though we should have a warning on the lists of minor planets and comets. But for the DPs, Eris & Makemake, we should really have the actual dates of discovery. I know that's not directly relevant to the GAN for this article, but they're already FAs, and here it looks as though they're messed up. Could write Brown and ask him, I guess. kwami (talk) 07:54, 30 September 2008 (UTC)

surface expansion

I found some neat text here which might be a good starting point for expanding some of the ideas here - especially since it offers links to refs too. here's a neat example

The bright pure-ice surface of Haumea and its moons was unexpected. Observations of the primary body made by astronomer Chadwick A. Trujillo and his colleagues revealed the strong spectral signature of crystalline water ice. While crystalline ice forms at temperatures above 110° Kelvins (-163° Celsius), the ambient temperature of space around Haumea is much colder, at below 50° Kelvins. In addition, since crystalline water ice should turn dark and ruddy in less than 100 million years from cosmic rays and micrometeoroid impacts in a process known as space weathering. Given the orbital spread of the EL61 family of fragments, however, the collision that produced them must have taken place billions of years ago. Hence, the object may have experienced resurfacing, perhaps by micrometeorite impacts that convert surface ices to crystalline form by flash-heating.
Spectra of Haumea's outer satellite obtained by astronomers Kristina M. Barkume, Michael E. Brown, and Emily L. Schaller also reveal the signature of almost pure water ice (Barkume et al, 2006). While the observations were too low in resolution to distinguish the type of water ice, it seems that nearly all of the moon is coated in highly reflective frost, like the three moons of Pluto which may also have formed from a violent collision. Hence, the moons of the largest KBOs may differ in origin from those of ordinary KBOs, possibly because their satellite systems formed from the remains of violent impacts instead of by delicate gravitational capture (Noll et al, 2007; Stern et al, 2006 and 2005; and Brown et al, 2005)

Nergaal (talk) 19:24, 29 September 2008 (UTC)

There isn't anything in that quote that isn't mentioned in the article already. Serendi^podous 19:28, 29 September 2008 (UTC)

I take that back- a bit. There's some useful info in that Sky and Telescope article they copied. Serendi^podous 19:37, 29 September 2008 (UTC)

The problem with adding that piece of information is that it is not agreed on by the research community as the correct explanation. We went through the young surface issue already: Talk:Haumea_(dwarf_planet)/archive_1#Been_trying_to_get_to_grips_with_some_confusing_scholarly_papers. Anything that resurfaces Haumea has to be limited to a certain group of TNOs, otherwise there is no explanation for why most things in the Kuiper belt are less than shiny. Iridia (talk) 21:47, 29 September 2008 (UTC)

I thought the young surface thing had been put in - but it's down in the collisional family section. Will move it. Iridia (talk) 21:54, 29 September 2008 (UTC)

Temperature

Where did we get the temperature figures in the infobox from? Serendi^podous 19:54, 29 September 2008 (UTC)

Subbed it with a less exact but sourced temperature. Serendi^podous 12:56, 3 October 2008 (UTC)

moving?

to Haumea? The goddess will never be more famous than the dwarf planet, so I see no reason why the common name should not be assigned to this page instead. Nergaal (talk) 15:23, 7 October 2008 (UTC)

No; this isn't the same as the planets. Jupiter gets first seating because no one looking for the head of the Graeco-Roman pantheon is going to look for Jupiter. He or she is going to look for Zeus. Same with every other Roman god. There isn't such an alternative for Haumea. Serendi^podous 15:29, 7 October 2008 (UTC)

I think that most people looking for the god Jupiter, would inter Jupiter and not Zeus. Zginder 2008-10-07T16:48Z (UTC)

My point is that most people wouldn't be looking for the god Jupiter, they'd be looking for the god Zeus. Serendi^podous 16:49, 7 October 2008 (UTC)

In any case, Haumea is not likely to ever be well known. Even Mercury is a dab. Ceres is a dab. When there are 40 recognized DPs or more, it's going to be like the asteroids. kwami (talk) 20:17, 7 October 2008 (UTC)

The mercury example is completely not relevant since the element is actually more commonly encountered than the planet. My point is that whoever would look for Haumea, would most likely NOT look for the goddess. I would bet the same thing for Eris too. Ceres on the other hand is a fairly common god IMHO. I just think that obscure gods are not likely known, while present-day name of celestial objects might be more common. Nergaal (talk) 21:39, 7 October 2008 (UTC)

It seems to me that the goddess Ceres is more obscure than Eris, who pops up as an internet meme and a cartoon character. If I had to, I'd bet that far more people know the name Eris from the Cartoon Network and Discordianism than from astronomy. The point is that neither the deities nor the DPs are commonly known—they're all obscure, which makes them prime candidates for dab pages. As more DPs are accepted, Haumea, Eris, and Makemake will become individually less and less notable. The one exception is Pluto. kwami (talk) 23:00, 7 October 2008 (UTC)

It seems unfair that there should be so little information on the Haumea page - Eris has a much more complete article. Maybe a little bit of upgrading on that is in order as well, especially considering that there is a lot of detail over the naming on this page. Iridia (talk) 23:30, 8 October 2008 (UTC)

Well, I don't feel strongly about it either way. kwami (talk) 18:20, 16 October 2008 (UTC)

Should we just go for FA?

I don't think this article's going to get much better, and its GA seems stuck in purgatory. If we want to get it into the topic, that would seem the quickest way. Serendi^podous 16:52, 8 October 2008 (UTC)

I keep meaning to give the text another pass or two, but haven't gotten around to it. Might be motivating to have criticisms from the FAN to work on. kwami (talk) 18:29, 8 October 2008 (UTC)

The GAN wasn't as helpful as I've expected so I guess going to FAC soon is the next thing to do. Nergaal (talk) 04:50, 9 October 2008 (UTC)

So? When is the nom going to go up? Nergaal (talk) 22:53, 9 October 2008 (UTC)

We should probably decide whether we're going to use the FU image first, rather than trying to introduce it during FAC. kwami (talk) 00:09, 10 October 2008 (UTC)

Done! Going once! Nergaal (talk) 03:26, 12 October 2008 (UTC)

Going twice! Anything else missing before FAC? Nergaal (talk) 04:22, 12 October 2008 (UTC)

User:Iridia has said she wouldn't mind being listed as a co-nominator. Serendi^podous 10:05, 12 October 2008 (UTC)

Sure, I will create the nomination and whoever wants the conom should sign their name in. How does that sound? Nergaal (talk) 22:47, 12 October 2008 (UTC)

Going thrice! Nergaal (talk) 22:47, 12 October 2008 (UTC)

Done! There might be a few more problems with the refs so it would be nice if some of you would take a look at that section too. Nergaal (talk) 23:14, 12 October 2008 (UTC)

Nice model

I went to reference the current best model for thinking that TNOs are primordial relics of the Solar System's formation, and found that there is no page for it. Can we please discuss what content needs to be in a page on the Nice model? It is the current best model for explaining the LHB, the Kuiper belt truncation, the scattered disk, etc. etc. There's three main papers that constitute the model, Morbidelli et al. (2005), Tsiganis et al. (2005), Gomes et al. (2005). and a whole bunch of other ones since. From how it's covered at planetary migration, LHB and Kuiper belt, this should definitely be spun off to a separate page so that the pros and cons of the model can be discussed - it seems to be reported as a fait accompli, but there's a lot of details, particularly the Kuiper belt-specific ones, that it doesn't yet meet. Background here: http://www.sciencemag.org/cgi/reprint/sci;314/5799/590b.pdf?ck=nck and here: http://www.lpi.usra.edu/meetings/bombardment2008/pdf/3018.pdf Iridia (talk) 01:56, 9 October 2008 (UTC)

Go for it. Just write up what you think we need. We can work out the fine points later if anyone disagrees with you. kwami (talk) 22:04, 16 October 2008 (UTC)

moon(s) picture

one of the papers has a small caption where one of the moon is visible (the satellites in the Kuiper belt one). should we upload that image? at least it would be a real image, not an impression. Nergaal (talk) 04:56, 9 October 2008 (UTC)

Is it in the public domain? Serendi^podous 15:30, 9 October 2008 (UTC)

It is within the pdf file, but the fair-use rationale (or whatever it is called) might make it ok. Nergaal (talk) 15:42, 9 October 2008 (UTC)

I prefer not to trust FU rationales. They tend to get you into serious trouble down the road. Serendi^podous 15:44, 9 October 2008 (UTC)

It's always nice to have an actual photo. Pluto is FA with a FU main image, so I doubt this would be problematic. kwami (talk) 19:24, 9 October 2008 (UTC)

I would also prefer having a real image to, be it at poor quality. Nergaal (talk) 02:15, 10 October 2008 (UTC)

OK, I suppose it shouldn't cause too much trouble. Serendi^podous 07:08, 10 October 2008 (UTC)

I've uploaded the image from reference 33. Somebody who knows the license criteria please edit the image's entry. Nergaal (talk) 03:26, 12 October 2008 (UTC)

should the image be cropped? Nergaal (talk) 03:34, 12 October 2008 (UTC)

It would look better. kwami (talk) 03:55, 12 October 2008 (UTC)

Fair-use license in place. kwami (talk) 04:13, 12 October 2008 (UTC)

Palomar

Oops, Haumea was discovered at Palomar. Only the moons were discovered at Mauna Kea. kwami (talk) 21:53, 16 October 2008 (UTC)

circular reasoning?

In the second paragraph of Size, shape, and composition, we say that we calculate its density from its shape. In the third paragraph, we say that we calculate its shape from its density. Needs a fix or at least clarification. kwami (talk) 21:59, 16 October 2008 (UTC)

I don't know where that came from. Brown concludes that Haumea is mostly rock because its surface is mostly pure ice. see here. Serendi^podous 15:53, 17 October 2008 (UTC)

It might be an error I introduced in my rearrangement of the article. I'll try to fix it if you don't get it first. kwami (talk) 19:46, 17 October 2008 (UTC)

To be honest, the recent changes (last couple days) have left my head spinning. I'm not sure which way is up right now. Maybe you could have a go? Serendi^podous 19:51, 17 October 2008 (UTC)

Yes, sorry. Must have looped a little on my own sentence - I was writing that pretty quickly. (Serendipodous, that Trujillo et al. 2007 paper does not say anything about the internal composition, it only discusses the surface composition). The chain of reasoning for the rock composition should go like this: light curve period -> rotation (spin rate), spin rate + mass + light curve amplitudes + assumption of a Jacobi ellipsoid shape = density + shape + albedo, all linked parameters. The whole argument is in this paper, and I'm working on how to get it clear enough for the article. Iridia (talk) 21:53, 17 October 2008 (UTC)

Should be okay now. Iridia (talk) 00:45, 18 October 2008 (UTC)

moon separation 40° or 10°?

Okay, I'm not following something. In the abstract for one of his talks,[2], Brown says, "Unlike most close-in satellites, S2 is on an edge-on 18-day orbit with an eccentricity over 0.2 and a mutual inclination to S1 of over 10 degrees." What in the world does this mean? Is Namaka being torqued by 10°, so it's at 30° rather than 40°? What's an "edge-on 18-day orbit"? Something unusual about Namaka, but it sounds like he's describing the view from Earth. kwami (talk) 02:26, 18 October 2008 (UTC)

Ragozzine (not Brown) is describing the view from Earth. How I read it: the orbit appears edge-on from our view, with an 18-day period, and the relative inclination between the orbits of the two moons is >10 degrees. Iridia (talk) 02:36, 18 October 2008 (UTC)

That's a big change from 40 degrees! I can see the change in period from 34 days because of the large eccentricity, but was the initial orbital plane also that far off? kwami (talk) 02:47, 18 October 2008 (UTC)

And what is unusual about an 18-day orbit, or occasionally being seen edge-on from Earth? Or does he only mean that the eccentricity and inclination are unusual? kwami (talk) 02:49, 18 October 2008 (UTC)

The bit you I left out as being too detailed (sorry kwami, no offence intended - I'm making too many edits to my own writing!): they are non-Keplerian orbits, and perturbing each other vigorously, so it's really tricky to do the orbit determination. Brown's 2005 paper that we used to have as the reference there assumed circular, Keplerian orbits, without massive perturbation. This is a crazy and unusual system. It would be good to enlarge a little on that, but we might need to wait for more detail than one conference abstract to be published.

As for the edge-on: yes, that is also really unusual. The chances of it being edge-on right after discovery, when there's a century-plus window - well, the observers of extrasolar planets play games with large numbers to try and get those situations happening. Iridia (talk) 03:12, 18 October 2008 (UTC)

Could say something like this (knew I left the sentence around here somewhere): The orbits of the moons of Haumea are unusual as they cannot be described by simple Keplerian dynamics due to their strong mutual perturbations, which cause the orbits to precess exceptionally rapidly. Iridia (talk) 03:22, 18 October 2008 (UTC)

Should we mention the Kozai mechanism? It can alter the orbits of Nereid (moon) and Margaret (moon).-- Kheider (talk) 12:43, 18 October 2008 (UTC)

Of course we should, Iridia & Kheider. This is fascinating, and should be expanded as much as feasible, though perhaps the full details in moons of Haumea so this article doesn't get bogged down. It will also lead the reader to the other moons Kheider just mentioned.

How well can we ref this? Will the conference presentations be posted online, or are there other refs? kwami (talk) 18:44, 18 October 2008 (UTC)

The conference presentations were here, but have gone again (hopefully temporarily). We don't have anything to reference since nothing else has yet been published. There is just enough information in one of the abstracts that we could mention it is a non-Keplerian and peturbed situation, and say that this is unusual, but I don't know what else could be said. Iridia (talk) 19:03, 18 October 2008 (UTC)

We can reference the conference. I doubt that's a problem for FA, but if it is, we can always use it for the moons article. Looks like they're all in session 36? Thanks for the link! kwami (talk) 19:22, 18 October 2008 (UTC)

Expanded as much as feasible. Iridia (talk) 04:41, 20 October 2008 (UTC)

Nice work editing that, kwami. I think that's probably as good as it could be. Iridia (talk) 07:33, 20 October 2008 (UTC)

pronunciation

At the conference above, Brown's students pronounced Haumea with four syllables, so I've changed what we have to match. The moons were pronounced as we already have them (except one student who had trouble with the names and pronounced Hi'iaka as high-7eye-ah-kə). kwami (talk) 20:15, 18 October 2008 (UTC)

Did you go through the Internet Archive to get hold of the presentations? Iridia (talk) 20:24, 18 October 2008 (UTC)

Yeah, just the Google cache. Too soon to be in the Wayback archive. Brown didn't speak, unless I missed his talk. Not a lot of info, but some key tidbits. We can expect transits for the next 5 years, w 2 events expected next year. Chi squared values, Namaka procession ~20°. I'm sure they have N's semimajor, but didn't bother to give it. 2006 orbits just wrong, so I deleted that info from the articles. Collisional family now has 8 members; only covered the last 2, so I don't know which the 6th was. Brown's students from 1 hour into the Oct 13 10:30 session to the end.

Oh, and HST false-color images. kwami (talk) 21:44, 18 October 2008 (UTC)

So if all Brown's students had mispronounced Hiʻiaka at the conference, would its article claim that was its proper pronunciation, regardless of the spelling or pronunciation of the original Hawaiian? Near as I can tell, the Hawaiian name is three syllables: au is a diphthong, as in Niʻihau, Maui, etc, and there's no ʻokina to indicate the vowels should be separate (i.e. it's not Haʻumea). If Brown's students pronounced it as four syllables, it was likely just a case of hypercorrection, as I doubt any of them had any experience with Hawaiian, as evidenced by the trouble with Hiʻiaka.

We also have an Associated Press story announcing the naming of the planet, which gives a three-syllable pronunciation. Encarta also gives the three-syllable pronunciation. The pronunciation given at the conference is irrelevant to the proper pronunciation of the word, and the pronunciation given in the article should be changed. - 24.18.215.64 (talk) 12:30, 10 January 2009 (UTC)

Just to note, that Encarta article describes the collisional family of Haumea as "comets". If it makes a mistake like that, I feel less inclined to trust other parts of it. However, the point about hypercorrection seems possible, and since I have much less experience with Hawaiian than with te reo Māori, I'll leave this reopening of the discussion to kwami's opinion. Iridia (talk) 01:53, 11 January 2009 (UTC)

One student had clear problems with the names, not all students. My understanding of Hawaiian "diphthongs" is that they're defined by how they affect stress more than how they're actually pronounced, which is more like Japanese vowel sequences. But I don't see any problem with having both pronunciations, even if the sources aren't very credible. kwami (talk) 08:29, 11 January 2009 (UTC)

Main page submission?

Should we consider putting Haumea up for main-page featured article in late December? There is the association of the initial nickname with Christmas (+1), +1 for basic subject matter (maybe more for being high-importance in Wikiproject Solar System?), and if one of the main contributors who hasn't had a featured article on the main page puts it forward it can get another +1 for contributor history. The question would be if being in the month after Volcanism on Io and two months after IK Pegasi means it is classified as "similar" to those articles, when it would lose two points; otherwise it gains one point for no similar article being featured in the preceding three months, and it would easily make the list.

Alternatively, we could wait for the anniversary of the discovery of one of the moons, and get a definite +1 that way. Iridia (talk) 02:32, 26 November 2008 (UTC)

We could nominate it on the anniversary of its discovery, that might give it more of a push. Serendi^podous 13:05, 26 November 2008 (UTC)

Okay, I'll submit it later today to see if anyone else comments first, but will put it up for main-page on 28th December. Iridia (talk) 17:23, 26 November 2008 (UTC)

Submitted. Iridia (talk) 23:40, 26 November 2008 (UTC)

Turns out Ceres was already on the list, for the 1st of January. Ah well. Iridia (talk) 01:33, 27 November 2008 (UTC)

Artist's conception is misleading

This picture is misleading as it looks like a photo but is not. Yes it is explained in the caption but it's small and easily overlooked. I tried to add bold to the Artist's conception part but it doesn't seem to work in this box so maybe someone else has an idea how to do this. Some other articles like http://en.wikipedia.org/wiki/Ellipsoid link to this picture without even explaining its a drawing. There is a real photo of Humea below and I think it would be preferable to include that one instead in the box ("2003 EL61.jpg") or at least as I said it should be more prominent that the one presented is artist's conception. Artist's conception is nothing more then a fiction, which might or might not reflect reality. In this particular case the size of the moons and their position is quite misleading. Enemyunknown (talk) 15:27, 19 December 2008 (UTC)

Done, per the other planet/dwarf planet articles. --Ckatz^chat_spy 17:57, 19 December 2008 (UTC)

Haumea and my Birthday

Not that this would concern anyone, but my birthday is December 28. Isn't that the date Haumea was (supposedly) discovered? Pretty good coincidence, huh? —Preceding unsigned comment added by 75.104.128.37 (talk) 20:23, 3 January 2009 (UTC)

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
₋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. Serendi^podous 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^deeds 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? Serendi^podous 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? Serendi^podous 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 Wikipedia 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)