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Review: February 3, 2024. (Reviewed version).

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Diameter

Where did the old diameter of ~1386 come from? Now that I check the history logs I see that User:Michaelbusch kept re-instating it in place of wild guesses. User_talk:68.186.106.251 was the 1st to insert it on 11 Sept 2006 :-) Kheider 06:48, 8 November 2006 (UTC)

With abs mag (H)=3.8, even assuming an albedo of 0.04 in 2006 would have resulted in a diameter of only 1150. -- Kheider (talk) 18:52, 6 January 2010 (UTC)

Image

Needs an image (even though it will just be a dot!)Fig (talk) 13:33, 14 March 2015 (UTC)

External links modified

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Occultation size estimate

@Nrco0e: Regarding your addition Calculated from the projected elliptical dimension of 842 × 688 km, or triaxial dimension of 842 × 842 × 688 km. The mean diameter of 787 km is derived from the cube root of the product of the given triaxial dimensions., I wonder where you take the information about the triaxial dimensions from. The occultation does not give triaxial dimensions; it gives an elliptical cross section $a\cdot b$ , which may be assumed to be from a triaxial object with volume $a\cdot b\cdot b$ (it almost certainly isn't, but whatever). It is almost never $a\cdot a\cdot b$ for large bodies, even though this is possible. Do you have any source for why it should be the rare one (or the not-so-rare one, for that matter)? If not, I suggest to completely remove all of this, including the mean diameter. The source just doesn't give this information, and a lot of the assumptions must be WP:OR. Renerpho (talk) 04:43, 16 November 2019 (UTC)

There is one more mathematical quirk here: The fit 842 × 688 km is done with just two chords (four points), which is not enough to define an ellipse (even assuming that the two chords had perfect accuracy, which they don't). So, those numbers must come with considerable uncertainty (hundreds of km's in each axis, if I should guess; the uncertainty is not specified). Having a mean diameter based on a triaxial shape based on those numbers is questionable. Renerpho (talk) 04:48, 16 November 2019 (UTC)

Occultation of 26 July 2020

Successful observation of a stellar occultation tonight, which was actually streamed live via Youtube. The occultation is starting near the 39:43 minute mark, and took about 23 seconds. The prediction details can be found here. Note that this is the first of three occultations by 2002 MS4 this summer, the other two coming up on August 8th and August 12th. Renerpho (talk) 01:26, 28 July 2020 (UTC)

Cool! We're getting a lot of occultation data, so hopefully we'll see tighter numbers. — kwami (talk) 06:14, 21 June 2022 (UTC)

Ceres

Isn't Ceres the largest known planetoid without a moon? This google search says that it is just another term for asteroid and Ceres is the largest known asteroid. (I don't think 2002 MS₄ is an asteroid)108.46.173.109 (talk) 12:38, 1 May 2021 (UTC)

'Planetoid' is synonymous with 'minor planet'. Ruslik_Zero 17:36, 1 May 2021 (UTC)

3-sigma uncertainty

We are giving a 3-sigma uncertainty of abt. 14 days for the perihelion date. This may be a sensible thing to do, but right now the article doesn't say what that reason is. The reference gives dtp=4.6936 days (1-sigma), and there has to be a good reason not to follow that. We could point here for why 3-sigma is a reasonable choice for some data, although I still don't see why we don't just give the 1-sigma value from the source.Renerpho (talk) 05:39, 21 June 2022 (UTC)

Uncertainties are generally assumed to be 1 sigma unless stated otherwise. We don't state otherwise, so I changed it to 1 sigma. If there's a reason for 3 sigma, that can be restored with the reason added. — kwami (talk) 06:11, 21 June 2022 (UTC)

Potential names?

Is it known if there are any yet suggested? I don't even know where you'd start to look, but it seems odd that there aren't even any proposed ones from some time in the last 21 years. Or might it just be left as a number forever, as a deliberate piece of astronomical weirdness, seeing as it's now been so long? (How long did Albion run before being named, again?) 51.219.168.15 (talk) 13:31, 9 May 2023 (UTC)

There's always going to be a largest unnamed object, so in that sense it doesn't matter. Often ppl will hold off naming an object until they know enough about it to decide on an appropriate (as opposed to arbitrary) name, or until someone has something or someone to commemorate. There's a whole string of small, unremarkable asteroids named after students who won an annual science competition, but there are more stringent guidelines for these objects. If someone discovers something notable about MS4, we might get a name then. — kwami (talk) 04:47, 10 May 2023 (UTC)

Albion took just over 25 years to get a real name. Double sharp (talk) 16:07, 10 May 2023 (UTC)

Naming a common dwarf planet (as there are hundreds if not thousands of them) is not really a high priority or of scientific value. As I have known many of these objects by their "license plate numbers" for numerous years, I often find them getting a name making it more difficult to remember which one someone is talking about. -- Kheider (talk) 08:44, 11 May 2023 (UTC)

Too bad we can't find mythological names like 'Orten' or 'Emsephor'. — kwami (talk) 10:54, 11 May 2023 (UTC)

No, but already in the first thousand some of the final names alluded to the provisional designation. Consider 572 Rebekka = 1905 RB, 573 Recha = 1905 RC, 574 Reginhild = 1905 RD, 575 Renate = 1905 RE. Double sharp (talk) 16:37, 11 May 2023 (UTC)

Exactly what I was thinking, but harder to do that within the naming reqs of the IAU. — kwami (talk) 08:27, 12 May 2023 (UTC)

Salacia and Varda got named, so naming similarly-sized MS4 and AW197 isn't really that unreasonable in my opinion. Especially since they were discovered so early. Double sharp (talk) 16:54, 11 May 2023 (UTC)

The discoverers had no naming interest in it, probably. I would like to propose the name Jingwei.Chinese goddess.± — Preceding unsigned comment added by 文爻林夕 (talk • contribs) 11:11, 15 June 2023 (UTC)

GA Review

Passed, self-closing at request of reviewer. Nrco0e (talk) 19:59, 3 February 2024 (UTC)

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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This review is transcluded from Talk:(307261) 2002 MS4/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: CactiStaccingCrane (talk · contribs) 02:28, 17 December 2023 (UTC)

Very interesting asteroid. I am not an expert about asteroids in general so I will focus more on formatting and copyediting, though I will review the sources to the best of my ability. CactiStaccingCrane (talk) 02:28, 17 December 2023 (UTC)

P.S. No quid pro quo here, but could you also help reviewing Mars Society GAN? That article is really short and I would be very grateful if you do so. CactiStaccingCrane (talk) 02:31, 17 December 2023 (UTC)

Sorry, I'm too busy to help review other GANs. Plus, I'm going on a 4-day vacation tomorrow so I won't be available to respond if you happen to finish your GA review of this article during that time. Nrco0e (talk) 02:07, 24 December 2023 (UTC)

Hi @CactiStaccingCrane, it's been a while. Have you gotten around to reviewing this article yet? No rush of course. Nrco0e (talk) 17:41, 5 January 2024 (UTC)

I am very sorry that I have been too busy IRL lately. I will try to get the review done today. CactiStaccingCrane (talk) 01:30, 6 January 2024 (UTC)

Actually, I think I might not be the best person for verifying citations. I will ask for 2nd opinion for reviewing more technical aspects of the article. CactiStaccingCrane (talk) 01:35, 6 January 2024 (UTC)

Review

~~"in the Kuiper belt, a region of" -> "in the Kuiper belt, which is a region of" (for clarity)~~
"2002 MS4 has a diameter close to 800 km (500 mi), which approximately ties it with 2002 AW197 and 2013 FY27 (to within measurement uncertainties) as the largest unnamed object in the Solar System." -> "To within measurement uncertainties, 2002 MS4, 2002 AW197 and 2013 FY27 has a diameter close to 800 km (500 mi) and thus are the largest unnamed object in the Solar System." (again, for clarity)
~~"significantly improved 2002 MS4's orbit" -> "significantly reduced the uncertainty of 2002 MS4's orbit" (I assume here 'improved' as in a better estimation)~~
"Despite this, researchers do not consider 2002 MS4 to be in resonance with Neptune" – could you please clarify what exactly caused astronomers to think so? Is it because of insufficient evidence or the fact that its resonance is intermittent?

Comment: It's simply because astronomers don't classify 2002 MS₄ as a resonant TNO. Every paper (except for that one claiming the resonance) I could find about 2002 MS₄ calls it a classical Kuiper belt object. I'm not sure why it's only this paper that mentions 2002 MS₄ is resonant—there's no formal refutation to this claim, so I do not know if this is still correct or not. Nrco0e (talk) 03:57, 6 January 2024 (UTC)

~~"can make Earth-based observations" -> "can make observations" (space telescopes also have this issue, I think)~~
~~"it is approximately tied with" -> "it tied with" (redundancy)~~
~~"which would have made mass estimates possible" -> "otherwise estimation of its mass would have been possible" (avoid ambiguity of 'which' – is it referring to the minor planet or its moons?)~~
"for an assumed single-peaked light curve due to a spheroidal body with albedo variations" (might be worthwhile to explain this further in lay terms, as you have excellently done with other parts of this article)

Comment: I've decided to remove this part of the sentence since I don't think there's a need to distinguish the "single-peaked" nature of 7.33/10.44 hour period in the article, when the reference used for it does not discuss alternative possible rotation periods that are not single-peaked. For such a minor detail, I figured it would be better to explain it in a footnote instead. Nrco0e (talk) 03:57, 6 January 2024 (UTC)

I think that's a good idea too. CactiStaccingCrane (talk) 07:43, 6 January 2024 (UTC)

Overall, the article is very well written! I will try to review the citations as soon as possible, but because I am not an expert about this topic, I have asked for a second opinion for reviewing this article. CactiStaccingCrane (talk) 02:01, 6 January 2024 (UTC)

@CactiStaccingCrane: Thanks, I appreciate it. Nrco0e (talk) 03:58, 6 January 2024 (UTC)

2O on citations

Because of time: @CactiStaccingCrane:, @Nrco0e:.

I am no astronomer, but I do edit in the general natural-sciences area. To my eye, all of the citations used are scientific papers (definitely acceptable) or publications by either the Jet Propulsion Laboratory or the Minor Planet Center, which I assume are considered reliable astronomy sources. My only concern is that and are theses, which are not necessarily acceptable sources. Nrco0e, please justify their use. Happy editing, SilverTiger12 (talk) 20:02, 25 January 2024 (UTC)

@SilverTiger12: So you're talking about the theses of Peng and Thirouin? I assure you they're reliable. Peng works with researchers from the New Horizons mission (thesis supervised by JJ Kavelaars) and has co-authored one refereed paper, Verbiscer et al. 2022. They've been working on New Horizons observations of 2002 MS₄ since 2020. For Thirouin, she is an active researcher in minor planets and has over 50 refereed publications. Although some figures from her PhD thesis (i.e. rotation period of 2002 MS₄) weren't formally published as standalone papers, I would consider it reputable since several papers have cited the 2002 MS₄ rotation period directly from her thesis. For example, ADS says 10 papers have cited Thirouin's thesis--such papers include Verbiscer et al. 2022 on New Horizons observations and Rommel et al. 2023 on 2002 MS₄ occultation. Nrco0e (talk) 20:23, 25 January 2024 (UTC)

Thank you, those are good arguments for including them. I'd give this article a pass on citations. SilverTiger12 (talk) 20:36, 25 January 2024 (UTC)

@CactiStaccingCrane:? SilverTiger12 (talk) 21:31, 2 February 2024 (UTC)

I think the article meet ga standards for me as well. Since I don't have PC access today, feel free to self close this nomination @Nrco0e. CactiStaccingCrane (talk) 07:18, 3 February 2024 (UTC)

@CactiStaccingCrane: Done. Thank you and @SilverTiger12: for the review! Nrco0e (talk) 19:59, 3 February 2024 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Dwarf planet or not, what's the current consensus?

Today, the lede section was changed from

2002 MS₄ is large enough that astronomers consider it a possible dwarf planet.

2002 MS₄'s topographic features are among the tallest and deepest known for Solar System bodies, suggesting that it is not a dwarf planet.

I've reverted that, for now, because no explanation was given, and we are lacking a source (and so WP:PROVEIT applies). As I understand it, the October 2023 publication noted that such a topographic feature is possible, under certain assumptions about the object's internal structure; compare (307261) 2002 MS4#Topographic features. I read that to mean they're compatible with hydrostatic equilibrium. My questions are:

What's the current consensus among astronomers?
What examples do we have for the claimed "original" consensus, that astronomers consider it a possible dwarf planet?
Do we have evidence yet that the consensus has shifted since we learned of that large topographic structure? Renerpho (talk) 18:09, 30 November 2024 (UTC)

For the first point, it's ambiguous; there's no strong consensus in the literature. The classification of 2002 MS₄ as a dwarf planet is completely irrelevant to Rommel et al. (2023)'s occultation/topography paper as it is not their focus. Presenting Rommel et al.'s findings of massive topographic features as evidence against hydrostatic equilibrium (which is not discussed in depth in the paper) is therefore WP:SYNTHESIS.
Second point, see the citations (with page numbers) for the line Because of its large size, it is considered a dwarf planet candidate by astronomers. in the article body for specific examples of sources calling 2002 MS₄ a possible dwarf planet. Note that out of the 4 sources, one (Peng 2023) calls 2002 MS₄ a dwarf planet. Being an individual person's master's thesis, I don't think this source should be authoritative on what can call 2002 MS₄. Some other groups like Cook et al. (2023) and Zemouri et al. (2022) merely call 2002 MS₄ a "large KBO".
Third point, no. I could only find one paper published after Rommel et al. that mentions 2002 MS₄; this 2024 arXiv review paper on TNO occultations by Ortiz et al. merely calls 2002 MS₄ a "large TNO".

Nrco0e (talk • contribs) 18:54, 30 November 2024 (UTC)

@Nrco0e: Thanks! Mike Brown has also called it "nearly certainly" a dwarf planet. We're not necessarily looking for people who categorically call it a "dwarf planet"; merely for those considering it a "dwarf planet candidate" or "possible dwarf planet", or those who contradict that possibility.

@Kwamikagami: Maybe we should change the sentence in the lede to "2002 MS₄ is large enough that some astronomers consider it a possible dwarf planet", to indicate a lack of clear consensus? Renerpho (talk) 19:47, 30 November 2024 (UTC)

The point on SYNTH is well taken.

Brown hasn't updated his site in a decade, so I'm not sure we should count him any more than we do e.g. Tancredi. I'm not aware of any recent lit that considers objects smaller than Salacia to be likely DPs, though it would be interesting if there were. — kwami (talk) 11:11, 1 December 2024 (UTC)

@Kwamikagami: The last update to Brown's website is from May 5, 2023, about 18 months ago (a few months before the paper on 2002 MS₄'s occultation was published). This means Brown is using an outdated size estimate for it. It's WP:TOOSOON to tell whether he'll change his mind about it with the next update, or when that may be. If he does, he'll probably move it to his "highly likely" category. Renerpho (talk) 15:08, 1 December 2024 (UTC)

AFAICT he hasn't updated the larger bodies in much longer than that, though it's been a while since I checked. The 'updated daily' statement hasn't been true for at least a decade, which suggests he's not taking very good care of the site. — kwami (talk) 21:19, 1 December 2024 (UTC)

I've added the word "some" to the sentence in the lede, as proposed previously. Any objections? Renerpho (talk) 15:20, 1 December 2024 (UTC)

The wording 'consider it a possible dwarf planet' seems odd to me. As if 'possible dwarf planets' were a classification of objects like SDOs. I kept 'some astronomers' but tried different wording for the rest. I'm not particularly happy with that, but I can't think of anything better. — kwami (talk) 21:57, 1 December 2024 (UTC)

I agree yours is better; also, perfect is the enemy of the good. Renerpho (talk) 08:10, 2 December 2024 (UTC)

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