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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) 3:28, 11 December 2021 (UTC) [1].

Globular cluster

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Notified: WikiProject Astronomy, diff for talk page notification

Review section

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I am nominating this featured article for review because more than a month ago, Hog Farm stated on talk, "We've got lots of uncited text here, as well as many of the sources being from before 2005. This needs additional citations and an update with newer sources." There have not been any edits to the article since. I did not notify the FAC nominator as they have retired and not edited since 2014. (t · c) buidhe 17:54, 27 February 2021 (UTC)[reply]

  • Comment: can you explain why you arbitrarily picked the year 2005 as a cut-off criteria? Data collected from before that time should still be relevant. Praemonitus (talk) 18:24, 27 February 2021 (UTC)[reply]
    • Praemonitus I don't know how quickly research becomes outdated in this field but ideally one should only cite current/up-to-date research. The 2005 suggestion is from Hog Farm. (t · c) buidhe 18:29, 27 February 2021 (UTC)[reply]
      • I would have to say it depends on the subject. Some topics get researched more frequently, and others are more or less settled and rarely get an update. Praemonitus (talk) 18:32, 27 February 2021 (UTC)[reply]
        • @Praemonitus and Buidhe: - 2005 wasn't suppose to have any innate meaning, rather just more of a rough estimate of when most of the sources seem to predate. I lack the knowledge about the topic to deem the pace of research in this subject, but for an article about an active science, there are quite likely new discoveries and theories over the last 15 years. Although astronomy editors may have a better idea of the extent of that. Hog Farm Talk 19:18, 27 February 2021 (UTC)[reply]
References older than 2005 shouldn't automatically, or even generally, be considered inappropriate. Plenty of information isn't going to change, historical stuff most obviously, but also general background astronomy and physics. Obviously, any theories which have changed significantly in recent decades or are still in flux should have up-to-date references. Lithopsian (talk) 16:57, 28 February 2021 (UTC)[reply]
Fully agreed (@Lithopsian:). However, one thing that has changed since 2005 is the view that most globular clusters are simple stellar populations, which is now dead (but still canonical, so still worth mentioning). I've updated that with a 2018 review article. —Alex (Ashill | talk | contribs) 06:41, 1 March 2021 (UTC)[reply]
@Ashill recently saved Star pre-FAR. Does your interest extend to globular clusters? FemkeMilene (talk) 18:44, 27 February 2021 (UTC)[reply]
I took a quick look through. My impression is that the article is mostly pretty good. The statements that don’t have inline references are mostly what I would fit in the subject-specific common knowledge area of WP:WTC (things that are in any introductory astronomy textbook), so I wouldn’t challenge their verifiability. I tagged a couple things that could use improvement and can return when I have the time. Also, many of the older references are totally fine. Globular clusters are slightly odd in that they serve as a lingua franca of “standard” knowledge in astronomy, and Wikipedia should (and does) present that encyclopedic standard knowledge. That’s what older references in the research literature will state; newer ones don’t bother, not because the old references are outdated but because they’re common knowledge in the field. There are plenty of newer results that tweak that common knowledge with exceptions; this article does a good job, I think, of avoiding going down those rabbit holes citing new results. So I actually think it’s a good thing that this article avoids being based too much on new results. That philosophical comment aside, there are clearly some things that could be improved; I’ll try to work on it but may not have time for a while. —Alex (Ashill | talk | contribs) 15:39, 28 February 2021 (UTC)[reply]
I've added references everywhere that was tagged. No attempt to address older references yet. Lithopsian (talk) 20:57, 28 February 2021 (UTC)[reply]
  • Comments from Graeme Bartlett
    • Images need to have alt= text to improve accessibility.
Done. A little repetitive, I'm afraid, but then one glibular cluster looks a lot like another to the average reader. Maybe someone with more imagination could take a look. Lithopsian (talk) 17:18, 28 February 2021 (UTC)[reply]
    • Non-standard punctuation in use: “”
Done. Wretchskull (talk) 16:44, 28 February 2021 (UTC)[reply]
    • Awkward wording: "contains an unusual number of a type of star" (unusual number could be 0, 999, 1234, large - be specific)
Clarified to "unusually large". (The cited source simply said unusual; another source says unusually large.) —Alex (Ashill | talk | contribs) 06:07, 1 March 2021 (UTC)[reply]
    • I was expecting to see a diagram of where globular clusters are in a galaxy, but there is none there. This could be in #Orbits section
That's a good suggestion, although easier said than done. This one is OK (and public domain), although I'm not wild about the fact that they're not very clear to what extent it's an artist's conception and to what extent it is true positions of known globular clusters. There's a good one in Figure 1 of this paper, but we can't use it due to copyright. —Alex (Ashill | talk | contribs) 06:02, 1 March 2021 (UTC)[reply]
If we add a diagram like one of these, it should go next to the fifth paragraph in the observation history section, which describes the distribution of globular clusters in the Milky Way and its historical importance in demonstrating that the Sun is not in the middle of the Milky Way. —Alex (Ashill | talk | contribs) 06:11, 1 March 2021 (UTC)[reply]
This one? Artist's conception and it says so, labels the Sun and M4, but also has some other text that is a little dated. Lithopsian (talk) 15:50, 1 March 2021 (UTC)[reply]
If we could get the underlying image, that would be great. It's definitely an artist's conception of the Milky Way (can't have a real outside image that includes the Sun!) but may be real (modulo distance uncertainties) positions of globular clusters; the caption isn't clear about that. (That's my issue with the other one too.) —Alex (Ashill | talk | contribs) 17:33, 1 March 2021 (UTC)[reply]
    • One reference (94) uses authors list with non-standard affilliations.
Fixed. Lithopsian (talk) 17:21, 28 February 2021 (UTC)[reply]
I added a few author links (necessarily biased towards authors I know or know of, since I know they're worth checking for a link!). I did not link to Charles Messier in the ref list, since he's linked in the main text. —Alex (Ashill | talk | contribs) 05:51, 1 March 2021 (UTC)[reply]

Comments from Femke

I've looked through the article in search of sentences I believe need updating, and found a few.

  • A total of 152 globular clusters have now been discovered in the Milky Way galaxy, out of an estimated total of 180 ± 20 (source 1992)
  • Done (in fact, that 1992 source did not actually state the 152 number that I could find anyway, though by 2010 [the last update of the Harris catalog] it had only increased to 157). —Alex (Ashill | talk | contribs) 17:59, 10 March 2021 (UTC)[reply]
  • Blue stragglers are mentioned in two different locations. Is there a problem with structure?
This seems to be ok. Both locations, plus the image caption, appear to be sensible to mention this type of star. 2A02:C7F:7428:D200:9958:D746:E82D:FAD5 (talk) 16:15, 13 March 2021 (UTC)[reply]
  • However, a possible exception is when strong tidal interactions with other large masses result in the dispersal of the stars.
  • However about 20% of the globular clusters have undergone a process termed "core collapse". In this type of cluster, the luminosity continues to increase steadily all the way to the core region
Took a while, but I found and added a 2018 reference explicitly stating that that 20% number from a 1986 "preliminary" paper has stood up. —Alex (Ashill | talk | contribs) 03:16, 26 March 2021 (UTC)[reply]
  • A 2008 study by John Fregeau. Is this now common knowledge? If so, modren source + rephrase in wikivoice?
  • I deleted that paragraph. The paper hasn't been widely cited in the 13 years since, and it doesn't seem to be a significant change in our understanding of clusters (despite a somewhat overhyped press release resulting in some media coverage -- not uncommon), so I don't think this is really worthy of a mention, and certainly not a full paragraph. —Alex (Ashill | talk | contribs) 18:58, 10 March 2021 (UTC)[reply]
  • potential computing requirements to accurately simulate such a cluster can be enormous -> next paragraph indicated it was done in 2010, so not that enormous after all?
I clarified that that comment refers to a low-density cluster. I also added a ref from a few weeks ago showing that we're still very much pushing compute power -- saying it was "done" is relative, since there are still lots of approximations, and we need to make fewer as time goes on. —Alex (Ashill | talk | contribs) 00:14, 26 March 2021 (UTC)[reply]
  • How these clusters are formed is not yet known (2005 source)
How they form is still uncertain, but some progress has been made. See Forbes at el. (2018) for a decent overview, plus perhaps some of the modelling results since then. 2A02:C7F:7428:D200:9958:D746:E82D:FAD5 (talk) 16:20, 13 March 2021 (UTC)[reply]
The Forbes et al reference is more about generic GCs; I added it in that context. (It is indeed a good overview; there's more from there that could be incorporated.) I added a more recent ref from the same team that originally discovered the unusual clusters with a bit more of an idea about how they form (accretion from satellites). —Alex (Ashill | talk | contribs) 23:56, 25 March 2021 (UTC)[reply]
No joke, I think I've adequately addressed that last tag. Lithopsian (talk) 20:40, 1 April 2021 (UTC)[reply]
I went over the article once more, and put another set of cn tags in (sorry I didn't check thoroughly before). Six to go. FemkeMilene (talk) 15:46, 4 April 2021 (UTC)[reply]
Think I've got them all; thanks for your thoroughness. (Most were just mid-paragraph refs that also supported the untagged sentence after the ref, but these checks did lead to a couple minor but substantive tweaks.) —Alex (Ashill | talk | contribs) 04:10, 5 April 2021 (UTC)[reply]
SandyGeorgia comments

This is going to need a lot of citation cleanup before further prose evaluation can begin.

  • Why are these listed as "General sources", yet not formatted as the rest of the sources? They appear here as if they want to be External links rather than sources.
Yes, I'll move those to External Links. Separately, I think renaming the "Sources" section to "Further reading" makes sense. —Alex (Ashill | talk | contribs) 20:30, 7 April 2021 (UTC)[reply]
    • NASA Astrophysics Data System has a collection of past articles, from all major astrophysics journals and many conference proceedings. And "a collection of past articles" is non-specific; which articles are we looking at for sources? (We can't just tell our readers, well, somewhere in this collection of past articles you can find what you need to verify content in this article.)
Deleted. ADS is invaluable but isn't especially relevant to this article (not any more than it is to any astronomy article). —Alex (Ashill | talk | contribs) 20:30, 7 April 2021 (UTC)[reply]
    • SCYON is a newsletter dedicated to star clusters. Same, which are used as sources? Who is the publisher? Which authors? What makes them reliable?
    • MODEST is a loose collaboration of scientists working on star clusters. Same
  • "Review articles", not used as citations, should be alphabetical.
Done. —Alex (Ashill | talk | contribs) 20:30, 7 April 2021 (UTC)[reply]
  • "Books", Binnie and Spitzer each used only once, so why do they require a separate section, and Heggie is not used.
Spitzer isn't used either (a conference proceeding from the previous year is cited). I don't know this specific Spitzer book and don't have immediate access to it, but everything he wrote is brilliant, so it's easy for me to imagine that this book is worth including as a classic reference. Binney & Tremaine is a very widely-used dynamics book that is very relevant to this topic. I don't know the Heggie book, but it too looks relevant. To me, that looks like a decently-curated list of more-in-depth books for further reading, so my vote is to keep it as is. —Alex (Ashill | talk | contribs) 20:30, 7 April 2021 (UTC)[reply]
  • Footnote a seems to need a citation: Omega Centauri was known in antiquity, but Halley discovered its nature as a nebula.
That's stated in reference 10, which is right next to the footnote. (It refers to the object as having been named by Ptolemy, which is pretty direct evidence that it was known in antiquity, although in different words.) Should the reference move into the footnote? —Alex (Ashill | talk | contribs) 20:56, 7 April 2021 (UTC)[reply]
  • I eventually figured out that ESO = European Southern Observatory, which is neither linked nor clarified in any citation that used the abbreviation.
    • Example, this is an incomplete citation: "Ashes from the Elder Brethren". ESO. 0107. Missing date, missing access date, and tell us somewhere what ESO is. (There are others similar.)
  • Similar problem here with SEDS ... what is that ?
I have expanded the European Southern Observatory and Students for the Exploration and Development of Space acronyms in the references, used the press release templates, updated URLs and access dates where needed, and added ID numbers to releases for additional permanence. —Alex (Ashill | talk | contribs) 05:37, 10 April 2021 (UTC)[reply]
    • Frommert, Hartmut (August 2007). "Milky Way Globular Clusters". SEDS. Retrieved February 26, 2008. I can't get the site to load and can't even tell what it is, or whether it is reliable.
Works for me. I think this collection of pages is reliable; it's perhaps in a bit of a WP:SPS gray area. But it's also very carefully researched and exhaustive. —Alex (Ashill | talk | contribs) 05:37, 10 April 2021 (UTC)[reply]
  • Patrick Moore (2005). Firefly Atlas of the Universe. Firefly Books. ISBN 978-1-55407-071-8. This is a book, requires a page number.
  • This is missing author ... "Messier 13 (M13) - The Great Hercules Cluster - Universe Today". Universe Today. May 9, 2016. Retrieved April 23, 2018.

I will stop there for now; this is only a brief sampling, and the sourcing and citations here need to be cleaned up before further evaluation of the content. Please review all sources and citations for completeness. I am very skeptical that this article can retain status, and filling in the missing citations is not the same as making sure the older content is verifiable to reliable sources. SandyGeorgia (Talk) 20:14, 6 April 2021 (UTC)[reply]

@Ashill can we have an update here? You identified a recent review article by Gratton, which would be good to have included in the text. You convinced me that the science doesn't change much, so I'll be satisfied if it's not used very extensively. Can the section on orbits be expanded? FemkeMilene (talk) 07:47, 18 April 2021 (UTC)[reply]
@Femkemilene I incorporated the Gratton reference in a few places. I also took the opportunity to cite a bit what hasn't changed much (eg basic understanding of formation). I merged the very short orbits section into the formation section, where it puts the significance of the orbits in context. I also merged a couple see alsos into the main text. —Alex (Ashill | talk | contribs) 03:39, 24 April 2021 (UTC)[reply]

I hope to work towards the end of the FAR. So let me give another (final?) list of things I'd like to see improved.

  • Some giant elliptical galaxies (particularly those at the centers of galaxy clusters), such as M87, have as many as 13,000 globular clusters -> uniquely in lede, and relatively old source. Lede should be a summary of the body.
I agree that this information should be in the body of the article, along with some obvious data like the number in the Milky Way, but there doesn't seem to be a good place where it would fit. Perhaps in the observation section? A new section? 2A02:C7F:FC49:3300:1B8:16B7:6A94:8124 (talk) 13:18, 1 May 2021 (UTC)[reply]
I moved those numbers in to the paragraph in the observation section about numbers in the Milky Way; I think it fits there. Simplified lede to just say there are lots of globular clusters in other galaxies. —Alex (Ashill | talk | contribs) 04:05, 2 May 2021 (UTC)[reply]
  • The retrograde orbit may suggest that ω Cen is the remnant of a dwarf galaxy which was captured by the Milky Way -> is this level of uncertainty (may + suggest) still valid with modern sources?
Still not entirely settled - added a recent paper on the subject. Lithopsian (talk) 20:45, 28 April 2021 (UTC)[reply]
Not sure what this refers to; if it's footnote 41 in this version (footnote 45 in the current version), the author, date, and access date are all listed. I also added an archive-url for that one. —Alex (Ashill | talk | contribs) 04:19, 2 May 2021 (UTC)[reply]
  • The typical distance between stars in a globular cluster is about 1 light year,[41] but at its core, the separation is comparable to the size of the Solar System (100 to 1000 times closer than stars near the Solar System) -> I don't know how wide the solar system is, so find it difficult to understand this sentence
Not only confusing, but wrong although it is an accurate reflection of what the reference says. I've provided a more correct reference and rewritten that sentence. Lithopsian (talk) 16:43, 28 April 2021 (UTC)[reply]
  • double parentheses: (more than 25 kiloparsecs (82,000 ly) from the center)
  • Globular cluster M15 may have an intermediate-mass black hole at its core. cn
That one is discussed in several sentences in the text; I copied the reference over to the image caption. Also tweaked the caption to more clearly reflect the fact that this claim is basically debunked. —Alex (Ashill | talk | contribs) 04:41, 2 May 2021 (UTC)[reply]
  • Note the characteristic "knee" in the curve at magnitude 19 -> don't speak to reader
Text tweaked. Lithopsian (talk) 16:11, 28 April 2021 (UTC)[reply]
  • The origins of these stars is still unclear, but most models suggest that these stars are the result of mass transfer in multiple star systems -> update needed.
I#ve added a much more recent reference and rewritten that sentence, although the sentiment is still the same. 2A02:C7F:FC49:3300:1B8:16B7:6A94:8124 (talk) 14:11, 1 May 2021 (UTC)[reply]
  • Examples of core-collapsed globular clusters include M15 and M30. -> cn
  • Precise velocities were obtained for nearly 15,000 stars in this cluster -> update needed
  • Sometimes the GC are referred to as M15, sometimes M 15. Consistency.
Done. I've gone with no spaces. Messier objects are almost universally abbreviated without a space, although Simbad is one of a very few exceptions. Lithopsian (talk) 15:55, 28 April 2021 (UTC)[reply]

FemkeMilene (talk) 19:41, 27 April 2021 (UTC)[reply]

  • There is some dense jargon in here; I had to click out of the lead multiple times to understand the lead. Also, "While his distance estimate was in significant error (although within the same order of magnitude as the currently accepted value), it did demonstrate that the dimensions of the galaxy were much greater than had been previously thought.[c]" is not sourced; rather the footnote looks like original research without a source. That is a brief glance; I don't understand a lot of the article. SandyGeorgia (Talk) 12:51, 30 April 2021 (UTC)[reply]
I'm struggling to find the dense jargon in the lead. Do you mean the bit about Latin? Heavy elements? Tidal forces? Most of the lead seems to be straighforward descriptions in plain English, although there are an unfortunate numbers of references, suggesting information that ought to be in the body. The Shapley piece is definitely a problem. I've tagged it. I'll look for a reference but it might need to be dropped. The footnote is pure original research unless a reference can be found. 2A02:C7F:FC49:3300:1B8:16B7:6A94:8124 (talk) 13:25, 1 May 2021 (UTC)[reply]
My apologies for the delayed response (real life stuff took over).
  • What is a "stellar density"?
Reworded to "concentration of stars". —Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
  • Spiral galaxy is not defined, and the reader is obligated to click out to know what it is.
Added "like the Milky Way"; hopefully that provides at least some suggestion of meaning without trying to define it. —Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
  • Ditto for galactic halo ... the lead should be digestible to a layreader, and the layreader should not have to click out to decipher the meaning of a sentence.
Clarified.—Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
  • Ditto for open cluster.
Clarified that both globular and open clusters are types of star clusters. —Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
  • What is the "Disk of a spiral galaxy"?
Added wikilink, and again hopefully referring to Milky Way provides a suggestion. —Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
  • Redundancies in this sentence ... and were formed as part of the star formation of the parent galaxy, rather than as a separate galaxy.
I've rewritten that whole paragraph; see next point. —Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
The WP:LEAD must be an overview that is digestible to readers who are not well versed in astronomy. SandyGeorgia (Talk) 23:14, 16 May 2021 (UTC)[reply]
The lead was missing any discussion of the history, and the discussion of formation and significance was a bit limited. I added to both, trying to provide more context. But I'm way too expert to really tell if it's digestible. —Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
Great Debate (astronomy) isn't exactly about Globular clusters, but is a focal point for many of the issues around the distances and distribution of them. This paper summarises that debate and categorises the important factors together with a precis of where Shapley was right and wrong. These could support a useful expansion of the information currently in the article: the statement that Shapley gave a distance and it was too high very much over-simplifies the history. Shapley gave a great many distances to the galactic centre, ranging from close to correct to more than double. He even came late to the idea that globular clusters had an asymmetric distribution indicating a spherical system with the sun off-centre. In 1915, he dismissed it when determining the distance to M13. 2A02:C7F:FC49:3300:1B8:16B7:6A94:8124 (talk) 13:59, 1 May 2021 (UTC)[reply]
Yes, that "distance estimate" sentence and footnote c are totally standard textbook statements; I added three textbook references which say the same thing in different ways at different levels. I also incorporated the Trimble paper above to be explicit about Shapley's distance estimates. —Alex (Ashill | talk | contribs) 04:04, 2 May 2021 (UTC)[reply]
  • Close without FARC -- Just solved a few more prose issues myself. I'm a bit on the fence here, but this has been open for months, and would like to draw it to a close. I'm sure there is room for further improvement... — Preceding unsigned comment added by Femkemilene (talk • contribs) 18:23, May 14, 2021 (UTC)
See new replies above. —Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
Continuing ...
  • why are metal rich and metal poor in quotes? See MOS:QUOTEPOV. Ditto throughout (eg, blue stragglers)
I guess that should be italics per Wikipedia style; it's defining/referring to terms. Changed. —Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
  • review linking, blue stragglers is used in an image caption before it is linked in the next section.
Moved the image to the section in which it's used. —Alex (Ashill | talk | contribs) 07:09, 17 May 2021 (UTC)[reply]
  • de-howevering may be useful ... However, the above-mentioned historic process of determining the age and distance to globular clusters is not as robust as first thought, since ... see See overuse of however and User:John/however. Ditto for also, in addition, etc ... User:Tony1/How to improve your writing has good information on these plagues of Wikipedia.

I picked the section on simulations for a prose check, as that is a topic I do understand ...

  • subdividing what? An efficient method of mathematically simulating the N-body dynamics of a globular cluster is done by subdividing into small volumes and velocity ranges ...
  • The simulation becomes more difficult when the effects of binaries and the interaction with external gravitation forces (such as from the Milky Way galaxy) must also be included. ... What is meant by " when ... must be included" ... why are they not always included, and why must they only sometimes be included?
  • punctuation of this sentence? Over long periods of time this will result in a dissipation of the cluster, a process termed evaporation ... should that be an endash rather than a comma?
  • Either this is a switch in tense or I am completely misunderstanding the meaning ... The ultimate fate of a globular cluster must be either to accrete stars at its core, causing its steady contraction,[119] or gradual shedding of stars from its outer layers.

I think this article could yet benefit from a closer prose review by non-content experts, although I believe we are on the road to a restored bronze star. SandyGeorgia (Talk) 23:27, 16 May 2021 (UTC)[reply]

"" I've gone through several of these with responses inline, although it looks like several of the comments no longer apply as the text they refer to has been edited out. —Alex (Ashill | talk | contribs) 07:06, 13 June 2021 (UTC)[reply]
    • "Star clusters are often assumed to consist of stars that all formed at the same time" By whom?
    • "observed M4 in 1764... Subsequently, Abbé Lacaille would list NGC 104, NGC 4833, M55, M69, and NGC 6397 in his 1751–1752 catalogue" How do these dates work out? Reordered the sentences to what I think was intended
    • "Globular" was used a handful of times—too informal? I like it occasionally for brevity but I'm not familiar with the topic.
The lede states that "globular" is an alternative way of referring to them, although I don't actually see that usage in the text. I don't think it's too informal and think it's useful to vary the writing, and I far prefer "globular" to "GC" as a shortened form. —Alex (Ashill | talk | contribs) 07:06, 13 June 2021 (UTC)[reply]
    • "Both can be regarded as evidence that supermassive globular clusters are in fact the cores of dwarf galaxies that are consumed by the larger galaxies" seems redundant to what we said a section ago
    • "The proportion of metals can thus be an indication of the age of a star in simple models" In simple models or in reality?
    • "The Dutch astronomer Pieter Oosterhoff noticed that there appear to be two populations of globular clusters" I changed this assuming there are other populations besides the Oosterhoff groups, but just wanted to make sure
    • Was wondering whether you all thought it was Wikipedia voice to say "our" when referring to the Solar System or Milky Way. I lean toward no, but I thought I should check.
I don't see the Solar System referred to at all. For the Solar System, "our" can resolve ambiguity between the Solar System every possible reader of Wikipedia lives in and planetary systems around other stars (which are sometimes themselves called solar systems). The Milky Way is unambiguous (but "the galaxy" isn't, so it's typically called "the Galaxy" (capital G) or "our galaxy" or "our Galaxy" to distinguish it from other galaxies), so I changed "our" to "the". —Alex (Ashill | talk | contribs) 07:06, 13 June 2021 (UTC)[reply]
    • "A blue straggler is thought to be formed from the merger of two stars, possibly as a result of an encounter with a binary system" What is "encountering" the binary system? A third star?
Between two binary systems is what the source says. Clarified. —Alex (Ashill | talk | contribs) 07:06, 13 June 2021 (UTC)[reply]
    • "Holger Baumgardt and collaborators" Not sure why we're singling their name out specifically; needs more context. I replaced with "Researchers" for now
    • "When the stars of a particular globular cluster are plotted on an H–R diagram, in many cases almost all of them fall on a relatively well-defined curve" seems to contradict "but nearly all globular clusters contain stars that formed at different times, or that have differing compositions" in the lead. Which is it?
Both. :) I've largely rewritten the H-R diagram section per this and other comments; I hope that clears that up. There are distinct populations which formed at different times in most/all globulars, but the two times are not very far apart. You really have to be looking with the newest camera on the Hubble Space Telescope to see the difference clearly, which is now stated in the main text of the article. (An image would help, but there aren't any free ones I could find; if I have time, I may try to find the data and create one that is suitably licensed.) —Alex (Ashill | talk | contribs) 07:06, 13 June 2021 (UTC)[reply]
Thank you, I will edit with this in mind
    • "The morphology and luminosity of globular cluster stars" What does "morphology" mean in this context? The shape of the curve they make on the HR diagram? I'm not a content expert but that seems like a weird—and unnecessarily complex—word to use
    • "the blending effect can introduce a systematic uncertainty into the cosmic distance ladder and may bias the estimated age of the Universe and the Hubble constant" what does this have to do with globular clusters
    • "Certain clusters even display populations absent from other globular clusters (e.g. blue hook stars) or feature multiple populations" don't most clusters feature multiple populations?
    • "gravothermal instability" what?
    • "forms a power-law cusp" I don't think most readers will understand this
    • The second paragraph of "Mass segregation" etc. really confuses me. I don't understand how the first sentence relates to the rest of the core collapse description
    • "this stellar mass-sorting process" Again, I didn't hear anything about mass in the preceding paragraphs, so I'm really confused
    • "Numerical simulations of globular clusters have demonstrated that binaries can hinder and even reverse the process of core collapse in globular clusters." Didn't we talk about this earlier?
  • Not sure how FARC works but agreed with Sandy that the writing is a bit off. I twiddled about with the first couple sections; see if that helped at all. The reading difficulty is highly variable... in particular the Color-magnitude section begins with a relatively detailed explanation of HR diagrams that I think could be shortened. But I don't see anything deal-breaking. Cheers, Ovinus (talk) 17:32, 9 June 2021 (UTC)[reply]
    • @Ashill: By the way, thank you so much for your work on this. The article is just a bit long but I'll get to your comments and everything soon. I think the article is a bit easier to parse so far. Ovinus (talk) 22:25, 18 June 2021 (UTC)[reply]
    • I went through and did a copyedit + adjustment of material I thought was way extra. But after the above concerns, I'm not opposed to keeping the bronze star. Ovinus (talk) 01:35, 19 June 2021 (UTC)[reply]
Drive by comment

Should ", constraining estimates of the universe's age." be moved from the lead as a historical detail? Chidgk1 (talk) 12:46, 23 June 2021 (UTC)[reply]

  • Could we get an update on status here? Nikkimaria (talk) 01:58, 10 July 2021 (UTC)[reply]
  • Move to FARC: I did a quick skim of the article and here are some concerns: three paragraphs of uncited text, "Mass segregation, luminosity and core collapse" should be copyedited and trimmed, and the classification section might be expanded (it talks about a 2015 proposal for reclassification, is that still ongoing?) No major edits since mid-June and Ovinus has not edited since late-June. Ashill or Lithopsian might be interested in leading these improvements, as they commented above. If work continues, I'll strike my suggestion to move to FARC. Z1720 (talk) 16:54, 23 July 2021 (UTC)[reply]
  • Move to FARC - work on the article has been stalled for a month, and I still have concerns
    • There's some uncited text yet that needs to be assessed for common knowledge or not
    • "It is unclear why the Milky Way lacks such clusters; Andromeda is unlikely to be the sole galaxy with them, but their presence in other galaxies remains unknown" - Got a source more recent than 2005 to confirm that this is still unclear
    • Any updates on that 2015 classification proposal?
    • Some sources need page number citations, such as Moore 2005
    • Are we sure Universe Today is high-quality RS

This is getting a lot closer, but there's work needed yet, and this is getting a bit stalled out. Like Z1720 above, I'm willing to strike this move to farc if work resumes. Hog Farm Talk 23:58, 24 July 2021 (UTC)[reply]

FARC section

[edit]
Issues raised in the review section include sourcing and prose. Nikkimaria (talk) 03:19, 31 July 2021 (UTC)[reply]

HF

  • I find it odd that Omega Centauri is the one picked out in the lead as being known from antiquity, but it's relegated to a table and an uncited footnote in the body. It's either going to be significant enough to warrant more mention in the body, or not significant enough to get a prominent namedrop in the lead
    • Good point. It turns out that Halley simply thought Centauri was a nebula; Herschel discerned that it was a star cluster in the 1830s. I removed it from the table and put it in the text
  • "and 157 in 2010" - of the refs for this, the second looks fine, but the first ref for this is from 1996? Why is it there supporting information from 14 years after it was published?
    • The 1996 ref already references "~150 clusters"... I skimmed the internet for more recent information on the exact number of known clusters but couldn't find much. In the mean time I've hidden that ref and added a more recent one (2017) that says "more than 150"
  • "Some giant elliptical galaxies (particularly those at the centers of galaxy clusters), such as M87, have as many as 13,000 globular clusters" - This is hypothetical, right, since this is much in excess of the confirmed number? But why is it stated as a matter of fact?
    • Clarified that the count of globular clusters is referring to clusters of the Milky Way, not of all galaxies
  • "In 1927–1929, Shapley and Sawyer categorized clusters" - who is Sawyer?
    • Someone oddly put Sawyer's name incorrectly in the text and piped it to her article. Fixed
  • " In 2015, a new type of globular cluster was proposed on the basis of observational data: dark globular clusters" - is it worth saying who proposed this?
    • Done
  • After further reading, the uncited paragraph seems to just be a description of a how a specific type of graph is set up, I'd say that's probably fine per WP:WHENTOCITE.
    • I'll look for a suitable citation anyway Found one that seems appropriate. Funnily enough it's more about the pedagogy of H–R diagrams, and in the process describes things in a simpler way as the article text does
  • "A blue straggler is thought to be formed from the merger of two stars, possibly as a result of an encounter between two binary system" appears in the Exotic components section, while "How blue stragglers form remains unclear, but most models attribute them to interactions between stars, either by stellar mergers or by the transfer of material from one star to another." appears in the Consequences section. I don't think this is really contradictory, but it would probably be best to discuss blue straggler formation in one place, rather than in two
    • Good point; I moved most of the information about blue stragglers to the first section and mentioned their distinctive appearance in the H–R diagram in the latter section
  • Recommend citations for "Core collapse may be divided into three phases. During a cluster's adolescence, core collapse begins with stars nearest the core. Interactions between binary star systems prevents further collapse as the cluster approaches middle age. Finally, the central binaries are either disrupted or ejected, resulting in a tighter concentration at the core." - It's not as elementary as the H-R diagrams
  • Is the uncited stuff in the Tidal encounters section basic knowledge? I'm not sure. If not, it needs cited
    • Will take a look for the above two. I don't have access to many sources at the moment; this has detailed information on core collapse, especially its models, but I don't see anything about three phases. I'd say "The difference in gravitational strength between the nearer and further parts of the cluster results in an asymmetric, tidal force" is common knowledge as the definition of tidal force, but the rest needs to be cited. The source I just mentioned does talk about "gravitational perturbations" but not "tidal forces" per se.
  • " Bennett, Jeffrey O.; Donahue, Megan; Schneider, Nicholas; Voit, Mark (2020). The Cosmic Perspective (9th ed.). Pearson. ISBN 978-0-134-87436-4." could use page numbers for better verification (if possible)
  • " "ESA/Hubble Picture of the Week". Engulfed by Stars Near the Milky Way’s Heart. Retrieved June 28, 2011." - formatting error. The Engulfed by Stars ... should be the title, and the true publisher needs added
    • Done, I think
  • "Schwarzschild, Martin (1958). Structure and Evolution of Stars. Princeton University Press. ISBN 978-0-486-61479-3." - could also use page numbers for verification
  • NO ACTION NEEDED - just noting that I've looked at the self-published Dave Pooley source, and as he helped discover SN 2006gy, I'd say he's probably a subject-matter expert for stars

This come a long way from when it started in FAR. I see Amitchell125 has done some work on this; do they have any further thoughts here? Hog Farm Talk 19:22, 4 September 2021 (UTC)[reply]

I've sort of stopped. Please don't wait up. Amitchell125 (talk) 08:17, 24 September 2021 (UTC)[reply]
@Ovinus and Ashill: - Would either of y'all be willing to look at this? If it can be determined what needs cited and what is fine, the rest should be easy fixes. Hog Farm Talk 15:11, 24 September 2021 (UTC)[reply]
@Hog Farm: I'm on the fence about marking this article as FA quality, although this is my first FAR so I'm not sure exactly what is required. I'll take a look anyway and responded to your comments above. Cheers, Ovinus (talk) 21:07, 24 September 2021 (UTC)[reply]
Comments by Z1720

In an effort to get this FAR closed, I am going to conduct a review of the article. I am not an expert in this field (I barely passed grade 10 science) so I will post questions and concerns below. I also conducted a copyedit while reviewing, so please review the changes to ensure I did not inadvertently change the meaning of a sentence.

  • "Some clusters display populations absent from other globular clusters (e.g. blue hook stars)" blue hook stars doesn't have a wikilink, and I don't know what this is. Can a different example be given here?
  • "may bias the estimated age of the Universe and the Hubble constant." Is Universe supposed to be capitalised?
  • There's a citation needed tag in "Mass segregation, luminosity and core collapse"
  • "Mass segregation, luminosity and core collapse" can possibly be combined into fewer paragraphs.
  • The first paragraph of "Tidal encounters" needs a citation
  • Why are the books and articles listed in "Further reading" not used as sources?

Those are my thoughts. My analysis is the first couple of sections have received more attention than the last few sections, so I recommend that an expert reviews the last sections for comprehensiveness and proper grammer. Z1720 (talk) 23:25, 2 October 2021 (UTC)[reply]

  • Could we get an update on status here? Nikkimaria (talk) 17:46, 23 October 2021 (UTC)[reply]
    • I fixed the few key missing citations. As I said in August, I don't think there are any outstanding issues presented above that currently prevent the review from being closed as Keep. Sportsfan77777 (talk) 23:39, 31 October 2021 (UTC)[reply]
    • Early on, I was concerned about the lead. Eight months in (!!), that is all I have time to review. It is digestible now, but I have one question:
      • Although one globular cluster, Omega Centauri, was observed and thought to be a star in antiquity …
    • What is a “star in antiquity”? Or is the in antiquity in the wrong place, and supposed to observed in antiquity ? SandyGeorgia (Talk) 23:58, 31 October 2021 (UTC)[reply]
It was "thought to be a star in antiquity"; i.e. "In antiquity, it was thought to be a star". Sportsfan77777 (talk) 00:55, 1 November 2021 (UTC)[reply]
Can that be fixed? SandyGeorgia (Talk) 01:16, 1 November 2021 (UTC)[reply]
Sure, done. Sportsfan77777 (talk) 01:20, 1 November 2021 (UTC)[reply]

@Sportsfan77777: Sorry for the delay in additional comments. Here are some thoughts:

  • For footnotes, are notes listed first, or are citations? This needs to be standardised.
  • I reordered the "History of observations section" to be more chronological. Please take a look to make sure I did not inadvertently change the meaning of something.
  • "It has been proposed that this multiplicity in stellar populations could have a dynamical origin." Who proposed this?
  • The notes need citations.

Those are my comments after this readthrough. I will admit that lots of this article is too technical for me to understand, however I think the technical aspects of this article require the prose to be more technical, and I predict that an undergraduate student in physics or mathematics will be able to understand its prose. Please ping me when ready for another readthrough. Z1720 (talk) 02:21, 15 November 2021 (UTC)[reply]

Z1720, what issues are outstanding from your perspective? Nikkimaria (talk) 02:27, 4 December 2021 (UTC)[reply]
  • I think this article is fine. If the body is not entirely digestible to a layreader, that can be expected for technical topics. Earlier on, the lead was a mess, but now it is fine for a layreader. Once Z1720 is satisfied, I am a Keep. SandyGeorgia (Talk) 15:10, 3 December 2021 (UTC)[reply]
  • Keep - I'd like to see a citation for " Harlow Shapley’s error was aggravated by interstellar dust in the Milky Way, which absorbs and diminishes the amount of light from distant objects, such as globular clusters, that reaches the Earth, thus making them appear to be more distant than they are." (one of the notes), but the remaining issues don't warrant delisting. Hog Farm Talk 15:53, 3 December 2021 (UTC)[reply]
  • I'll declare keep, although my notes above will need to be addressed at some point. I'll assume the notes are cited to the refs that are placed before it. Still not sure who proposed the multiplicity, but hopefully someone will come later to fix this. Z1720 (talk) 04:02, 4 December 2021 (UTC)[reply]
  • Closing note: This removal candidate has been kept, but there may be a delay in bot processing of the close. Please leave the {{featured article review}} template in place on the talk page until the bot goes through. Nikkimaria (talk) 03:28, 11 December 2021 (UTC)[reply]
The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.
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