Wikipedia:Featured article review/Kreutz sungrazer/archive1


 * The following is an archived discussion of a featured article review. Please do not modify it. Further comments should be made on the article's talk page or at Wikipedia talk:Featured article review. No further edits should be made to this page.

The article was kept by Nikkimaria via FACBot (talk) 4:21, 6 April 2024 (UTC).

Kreutz sungrazer

 * Notified: Worldtraveller, Ruslik0, Jqmhelios, WP Astronomy, noticed in 2021

As noticed by SandyGeorgia in 2021, this featured article last formally reviewed in 2008. There are prose issues (perhaps best exemplified by the admonition to "see below"), as well as dated text such as sourcing a list of discovery statistics to a source last updated in 2008, "The continuing discovery of large numbers of the smaller members of the family by SOHO will undoubtedly lead to a greater understanding of how comets break up to form families" from a source from 16 years ago, and similar. I don't think this will be a hard save, but this does need work. There are also more recent sources that should likely be consulted, such as, , and others. Hog Farm Talk 04:43, 2 September 2023 (UTC) Gonna do some work here, beginning with some unsourced paragraphs. Given what is said above, I guess that these are the sources that need to be included? Some questions: Jo-Jo Eumerus (talk) 07:04, 18 October 2023 (UTC)
 * Move to FARC while some edits have been placed in the article, there is still more work to be done, particularly in sourcing the "Discovery and historical observations" section. Z1720 (talk) 01:00, 16 September 2023 (UTC)
 * Move to FARC, no engagement since Z's last comment. Sandy Georgia  (Talk)  19:31, 17 October 2023 (UTC)
 * I note that not all sources seem to exclude the Great Comet of 1680 from this group, but most apparently do?
 * Is this an adequate source for the inclination & semiminor axis of the Kreutz group?
 * Are folks fine with using this source for the luminosity of Comet White–Ortiz–Bolelli? It's a private website by Gary W. Kronk who has some well-cited publications on comets.
 * Should we keep the list of individual comets?
 * - sorry for the late reply; I've been quite busy IRL the last couple months. I don't know enough about the topic matter to opine on the list or the Great comet of 1680, but I don't see any issues with using Monthly Notices of the Royal Astronomical Society for the inclination or semiminor axis. To me it seems like Kronk meets WP:SPS and should be an acceptable source. Hog Farm Talk 03:06, 6 November 2023 (UTC)
 * Sorry, I meant in the sense of values - finding a source that says "X and Y are the typical values of the inclination and axis of Kreutz comets" is tough. I see that I need to expand my list of sauces to use, probably will work them in tomorrow. Jo-Jo Eumerus (talk) 13:22, 6 November 2023 (UTC)
 * I can't access the particular source but trust your judgment on this matter. Hog Farm Talk 02:44, 7 November 2023 (UTC)
 * Make this another few days; the thing I hoped to finish yesterday will take longer. Jo-Jo Eumerus (talk) 07:52, 7 November 2023 (UTC)

Alright, expansion's now underway. Some comments: Jo-Jo Eumerus (talk) 14:41, 8 November 2023 (UTC)
 * Is this exocomet system worth mentioning? It seems to be discussing a general comet family rather than a Kreutz-like family.
 * This paper proposes the 467 AD comet as the most likely progenitor, but w/o discussing previous appearances.
 * This source has parameters named Lq and Lp which I don't understand; are they worth listing? This one has similar parameters.
 * I don't think this theory of an interstellar origin is mainstream, but as seen from discussions of Machholz it may be a minority opinion worth noting.
 * This paper presumes that the comets may have left dust trails, then says it can't see them, maybe because they are too far away.
 * Here a book discusses one of the comets colliding with the Sun and altering the corona - dunno if worth noting.
 * A somewhat theoretical discussion on carbon/hydrogen ratios of one of these comets.
 * A discussion on polarization of one of these comets.
 * Is X 1882 K1 or C or whatever here the same as the 1882 comet in the article?
 * Here's a discussion on the brightening behaviour of these comets and here's one indicating that they might not have an uniform luminosity
 * Source discussing a prediction of increased Kreutz sungrazer occurrence which was predicted in 2007 but doesn't seem to have come to pass.
 * A discussion that might contain compositional data
 * Great Southern Comet of 1887 might merit its own section.
 * I am not sure that the current section layout is ideal.
 * For the sake of simplicity, I don't update citations to newer ones if the new one merely supports something already said in the article. This book and this one may be useful if doing that is necessary.


 * Maybe would look at your list ? Sandy Georgia  (Talk)  15:17, 8 November 2023 (UTC)
 * Sigh. Just found out that apparently VE makes a complete mess out of pagenumbers - when you copy a reference and change the pagenumber in the copy, it seems to alter all of these citations. I'll avoid using it for the next batch but the previous one will need to have pagenumbers checked. Jo-Jo Eumerus (talk) 15:29, 8 November 2023 (UTC)
 * OK, cleaned that up. Someone ought to go through and see if some duplicate citations can be merged. Jo-Jo Eumerus (talk) 17:20, 8 November 2023 (UTC)
 * VE makes a complete mess of citations, period; abandon that MF. Sandy Georgia (Talk)  18:38, 8 November 2023 (UTC)


 * Could we get an update on status here? Nikkimaria (talk) 05:11, 25 November 2023 (UTC)
 * I've resolved the outdateness issues. I'd like to have comments from other people about the items on my dot-point list above and also a look-over on the prose quality, as that's the weak point of my FA(R) writing. Jo-Jo Eumerus (talk) 07:43, 25 November 2023 (UTC)
 * JJE, I'll give this a readthrough over the next week or so. Unfortunately, I won't be able to weight in very much on the list of specific subject matter questions - or ? I think this FA should be close to being keep-able. Hog Farm Talk 03:59, 6 December 2023 (UTC)


 * "It thus became the first known sungrazing comet. Its perihelion distance was just 1.3 solar radii, that is, its perihelion was 1.3 solar radii from the center of the Sun, and just 0.3 solar radii above the surface of the Sun." - given the very specific claims made here it should be cited
 * Removed this sentence wholesale as it adds nothing to the preceding paragraph. Jo-Jo Eumerus (talk) 16:59, 9 December 2023 (UTC)
 * "Other candidates are comets observed in 582 AD in China and Europe,[27] X/1381 V1 which was seen from Japan, Korea, Russia and Egypt," - it's unclear if these "other candidates" are for notable comets, the progenitor comet, or are candidates to be Kreutz sungrazers. I'm finding the whole first paragraph of the notable members section to be fairly confusing.
 * Specified this one a bit. It's a list of all these ill-documented comets where there is only little discussion on their membership. Jo-Jo Eumerus (talk) 16:59, 9 December 2023 (UTC)
 * "at which it reached an apparent magnitude estimated to have been −17, by far the brightest recorded for any comet and exceeding the brightness of the full moon by a factor of 57" - how does the math on this work, if -11 is stated to be comparable to only the first quarter of the moon later in the article?
 * I'd imagine it's because magnitudes are exponential - a difference of 6 magnitudes is equal to 10^(6*2/5)~251 times brighter. Jo-Jo Eumerus (talk) 16:59, 9 December 2023 (UTC)
 * The Great Comet of 371 BC section states "It [The Comet of 371 BC] is currently thought to have been the giant comet which progressively shattered under the influence of the sun to form the entire family of Kreutz sungrazers. " but then later in the article we get "One possible candidate for the grandparent is a comet observed by Aristotle and Ephorus in 371 BC. Ephorus claimed to have seen this comet break into two. However modern astronomers are skeptical of the claims of Ephorus, because they were not confirmed by other sources.[2] Instead comets that arrived between 3rd and 5th centuries AD (comets of 214, 426 and 467) are considered as possible progenitors of the Kreutz family" discussion the same comet
 * A common pitfall when updating an article is that you update section A and forget that something in section B needs changing as well. I've stripped out the Ephorus part from the 371 header. Jo-Jo Eumerus (talk) 16:59, 9 December 2023 (UTC)
 * The Great Comet of 371 BC section states that the original comet must have had a 120 km nucleus, but then we're told "The original comet must certainly have been very large indeed, perhaps as large as 100 km across [...] although a size of only a few tens of kilometres is also possible"
 * Typical "One source says this, another says that" case. Jo-Jo Eumerus (talk) 16:59, 9 December 2023 (UTC)
 * It's probably best to attribute these statements inline to the individual authors, then. Hog Farm Talk 17:34, 9 December 2023 (UTC)
 * Not sure that in-text attribution is also for non-opinion statements. Also, I'll need to check whether other people have remarked on this question. Jo-Jo Eumerus (talk) 18:14, 9 December 2023 (UTC)
 * "On average, a new member of the Kreutz family is discovered every three days" - this is word-for-word from the source. This isn't a big deal because the source is public-domain NASA materials, but it still would be best to reword this
 * Gonna have to pass here since I can't think of a better formulation. Jo-Jo Eumerus (talk) 16:59, 9 December 2023 (UTC)
 * I reworded that line a bit. XOR&#39;easter (talk) 17:02, 16 December 2023 (UTC)
 * " Some amateurs have managed remarkable numbers of discoveries, with Rainer Kracht of Germany having chalked up 211, Michael Oates of the United Kingdom making 144, and Zhou Bo of China spotting 97" - either newer numbers should be used or it should be mentioned that these counts are as of 2008; it's also unclear why these individuals are selected when the cited source indicates others have found 185, 105, and 100
 * Don't know either. Apparently that website compiled them from SOHO or Minor Planet Electronic Circulars and hasn't updated for a long time. Unless we can find another website that does it, we can't keep that block in the article. Jo-Jo Eumerus (talk) 16:59, 9 December 2023 (UTC)
 * I've tried snipping that part out; see what you think. XOR&#39;easter (talk) 17:10, 16 December 2023 (UTC)

I think we're getting closer, but there's still a bit of work needed here yet. Hog Farm Talk 16:36, 9 December 2023 (UTC)


 * Could we get an update on status here? Nikkimaria (talk) 04:28, 30 December 2023 (UTC)
 * I think we are waiting on regardin the "still a bit of work needed here" Jo-Jo Eumerus (talk) 07:23, 30 December 2023 (UTC)
 * I'll give this one another read-through when I get the chance but it might be a couple days. The article is definitely in much better shape than when I first listed it at FAR. Hog Farm Talk 15:48, 30 December 2023 (UTC)

Coming back to this ...
 * "For example, the Great Southern Comet of 1887 passed about 27000 km from the surface of the Sun." - in the lead but not in the body; if this is important enough for the lead then it should be in the body of the article as well
 * Aye, but first I need a WP:SYNTH check: According to this comet got 0.00483 au from the Sun, the closest among the Kreutz sungrazers of 1843-2011. That adds up to 27000km above the Sun's surface. Not sure that this is a case of WP:CALC given things like barycenter etc. Jo-Jo Eumerus (talk) 08:39, 3 January 2024 (UTC)


 * I honestly don't know if that meets CALC or not; math isn't my strong suit. We really need one of the astronomy editors to weigh in here - I'm getting in over my head with this one. Hog Farm Talk 17:53, 3 January 2024 (UTC)
 * That reference gives the perihelion (and other numbers) for the sungrazers discovered from the ground and doesn't particularly call attention to the 1887 comet. It gives the blanket statement, It is particularly noteworthy to highlight that their perihelion distances are very small: q < 0.01 au (i.e. less than about two solar radii), thus falling within the Sun's Roche limit. Would it make more sense to provide a statement like that instead of talking about one particular example? Also, I feel that less than about two solar radii is more dramatic for readers who don't instantly remember the Sun's radius in km. XOR&#39;easter (talk) 00:59, 8 January 2024 (UTC)
 * That would work better. Regarding the copies in the reference list, I suspect they are citing different page numbers. Jo-Jo Eumerus (talk) 06:54, 8 January 2024 (UTC)
 * We could merge the repeated instances and use rp to refer to specific pages. Or, we could gather the ones cited for different pages into their own list and cite them with sfn. XOR&#39;easter (talk) 15:57, 8 January 2024 (UTC)
 * I went ahead and took the sfn option, since there were a couple books that were also cited repeatedly with different page numbers. XOR&#39;easter (talk) 22:09, 8 January 2024 (UTC)
 * Oh, and there are three copies of that paper in the reference list. Likewise, there are 5 copies of "The science of sungrazers, sunskirters, and other near-Sun comets", and 6 copies of "20 years and 3000 objects later". Was the intent to refer to different pages? I think we generally don't bother with that for journal articles, as opposed to books, since the former are shorter. XOR&#39;easter (talk) 01:08, 8 January 2024 (UTC)
 * "A Kreutz sungrazer's aphelion is about 170 AU (25 billion km) from the Sun;" - is what the lead has, but then the body of the article has "The group generally has an eccentricity approaching 1, [...] an aphelion distance of about 100 AU ..." so that is an internal inconsistency
 * Changed. Jo-Jo Eumerus (talk) 08:39, 3 January 2024 (UTC)
 * Any possibility of a direct citation for the paragraph "This serendipitous event happened when the Eclipse Comet of 1882 reached its perihelion just as a total solar eclipse took place. The celestial alignment allowed observers to notice the comet against the darkened backdrop of the eclipse. This rare occurrence provided a unique opportunity for astronomers to identify and study the comet, which otherwise would have remained undetected due to its close proximity to the Sun during that period of the year."?
 * I asked the editor a few months ago and they didn't respond. I figure that there might be something here, but removed in the meantime. Jo-Jo Eumerus (talk) 08:39, 3 January 2024 (UTC)

This seems fine otherwise, but I would appreciate if we could get one of our astronomy editors to give this a third-party readthrough; I'm just not all that familiar with this group of comets. Hog Farm Talk 23:20, 2 January 2024 (UTC)


 * The specific reference to Canis Major is only found in the lead
 * "Ephorus claimed to have seen this comet break into two. However modern astronomers are skeptical of the claims of Ephorus, because they were not confirmed by other sources." is found in the Dynamical history section but we still have the Great Comet of 1106 AD section stating "Observations also suggest that the larger fragment of the Great Comet of 371 BC, which was observed splitting into two pieces" outright, which suggests that the language in the 1106 AD section about it splitting into two needs hedged a little bit as this is apparently disputed

This is all I noticed from another read-through, I think I'll be ready to support keeping this once these two things are addressed. Hog Farm Talk 23:07, 12 January 2024 (UTC)


 * Remedied. Jo-Jo Eumerus (talk) 07:46, 13 January 2024 (UTC)
 * I'm okay with closing without FARC here. Hog Farm Talk 17:30, 13 January 2024 (UTC)
 * One down, $$N - 1$$ to go.... XOR&#39;easter (talk) 21:46, 13 January 2024 (UTC)

need an update here. Jo-Jo Eumerus (talk) 10:15, 4 February 2024 (UTC)


 * Noting that Sandy hasn't been active lately, but Z1720 have your concerns been addressed? Nikkimaria (talk) 02:34, 5 February 2024 (UTC)

My comments have been addressed. Here are some other comments after a quick readthrough (some sections I skimmed, others I read thoroughly and copyedited). Note that I am not an expert:
 * I changed all the px to upright, per MOS:UPRIGHT. Feel free to change.
 * I added alt text to images, per MOS:ALT. Feel free to change to better wording.
 * Expanded one of these ALTs. Jo-Jo Eumerus (talk) 09:01, 12 February 2024 (UTC)
 * Why are there citations in the lede? Are these needed? From what I can determine, this information is cited in the article.
 * Removed them. Jo-Jo Eumerus (talk) 09:01, 12 February 2024 (UTC)
 * I'm not thrilled with the single-paragraph level-3 sections in "Notable members". Should some of these paragraphs be merged together?
 * I don't think so. A list is a list, trying to pass it off as a paragraph just makes it less readable. Jo-Jo Eumerus (talk) 09:01, 12 February 2024 (UTC)
 * There are various times that measurements are given in kilometres. Do imperial measurements also need to be given in these types of articles?
 * My understanding is that on such scientific topics one usually sticks to metric things. But if folks want to replace the kms with converts, I am fine with it. Jo-Jo Eumerus (talk) 09:01, 12 February 2024 (UTC)
 * I think using the convert template would be helpful. Z1720 (talk) 14:25, 8 March 2024 (UTC)
 * Done. Jo-Jo Eumerus (talk) 14:49, 8 March 2024 (UTC)


 * "Ikeya–Seki's derived orbital period gave a previous perihelion almost exactly at the right time," I'm not quite sure what this sentence is trying to tell me.
 * It means that the 1106 comet seems to be the earlier perihelion of Ikeya-Seki, or of a precursor of Ikeya-Seki. Jo-Jo Eumerus (talk) 09:01, 12 February 2024 (UTC)
 * Can this be simplified in the article? Z1720 (talk) 14:25, 8 March 2024 (UTC)
 * Done. Jo-Jo Eumerus (talk) 14:49, 8 March 2024 (UTC)


 * "Dynamical history and evolution" is quite long. Can this be divided by level 3 headings?
 * Not quite sure where to do this. Jo-Jo Eumerus (talk) 09:01, 12 February 2024 (UTC)
 * Since there are seven paragraphs in this section, can this be split into two, using level 3 headings? Z1720 (talk) 14:25, 8 March 2024 (UTC)
 * I don't think there is currently a structure that supports a split. Jo-Jo Eumerus (talk) 14:49, 8 March 2024 (UTC)

Those are my thoughts. Z1720 (talk) 18:23, 10 February 2024 (UTC)
 * Does the "Future" section violate WP:CRYSTAL? I think this can be moved to a better section, phrased more in Wikivoice, and updated for 2023.
 * Nah, orbital parameters are one of the more reliably predictable things. Problem is that I don't see many recent studies commenting on past predictions. Jo-Jo Eumerus (talk) 09:01, 12 February 2024 (UTC)
 * "About 83% of the sungrazers found by SOHO are members of the Kreutz group, with the others including the Meyer, Marsden, and Kracht1&2 families." This is cited from a report in 2008. Is this still accurate?
 * Don't think anyone has investigated this question since then. Jo-Jo Eumerus (talk) 09:01, 12 February 2024 (UTC)
 * "New Kreutz sungrazers are discovered roughly once every three days," Citation is from 2015. Is this still accurate?
 * Don't think anyone has investigated this question since then. Jo-Jo Eumerus (talk) 09:01, 12 February 2024 (UTC)
 * There's some overly-expressive language in the article, and some copyediting that needs to happen. I did some of it, but I ran out of time and would appreciate if someone with more subject-area knowledge would do a readthrough first.
 * Sorry that I did not respond earlier. Responses above. Z1720 (talk) 14:25, 8 March 2024 (UTC)


 * where are we at with this? Nikkimaria (talk) 18:09, 16 March 2024 (UTC)
 * Seems OKish on my end, but I can speak more of source completeness than prose. Jo-Jo Eumerus (talk) 07:34, 17 March 2024 (UTC)


 * ? Nikkimaria (talk) 18:31, 29 March 2024 (UTC)
 * I have been too busy in real life to take another close look at this. I'm OK if a decision is made without me. Z1720 (talk) 18:38, 29 March 2024 (UTC)

Nikkimaria (talk) 14:21, 6 April 2024 (UTC)
 * The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.