Misplaced Pages

:Featured article candidates/Rigel/archive1 - Misplaced Pages

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
< Misplaced Pages:Featured article candidates

This is an old revision of this page, as edited by Casliber (talk | contribs) at 11:41, 28 April 2020 (→Comments from Fowler&fowler). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Revision as of 11:41, 28 April 2020 by Casliber (talk | contribs) (→Comments from Fowler&fowler)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)

Rigel

Rigel (edit | talk | history | links | watch | logs)

Toolbox
Nominator(s): Lithopsian, Attic Salt & Cas Liber (talk · contribs) 23:19, 1 April 2020 (UTC)

I felt bad that Betelgeuse got lots of love and attention and its buddy Rigel was ignored...so a few of us astronomical-interested editors have been buffing this article for some time. After a few pauses and deep breaths (and second looks and a productive GA review from The Rambling Man, which was great for accessibility....here we are. This is a co-nomination so queries should be responded to pronto. Have at it. Cas Liber (talk · contribs) 23:19, 1 April 2020 (UTC)

  • Drive by comment: I wonder if it would be good to note that we have not found any planets orbiting these stars somewhere in the article? It's the first thing I looked for but could not find it. Mattximus (talk) 17:07, 2 April 2020 (UTC)
A good question....very bright stars are difficult to investigate, so many have not been investigated in this way. We'd also need a source saying that someone had (unsuccessfully) tried I think. I'll have a look. Cas Liber (talk · contribs) 23:46, 2 April 2020 (UTC)
Hard to find negative results like "no planets" getting published, even harder to find a scientific journal stating that nobody even looked around a particular star. At a guess, I'd say nobody has looked; there have been searches for spectroscopic companions, but finding a sub-stellar mass around a supergiant would be quite a feat. I did find one web page explaining some of the reasons why Rigel is unlikely to have any planets and why they might be hard to spot if it did. It would be a stretch to call it a reliable source. We could use one of the public exoplanet databases, for example the NASA exoplanet archive can be searched and will tell you that there are no entries for Rigel. Would obviously be a statement subject to change at any time in the future. Lithopsian (talk) 13:34, 4 April 2020 (UTC)
Opening confession: I know nothing about the topic; in fact, where I come from, it hasn't been invented yet :) In the references, you've got a number of books without publisher location. Also check book chapter for page spans, as anumber are also missing. Some journals are also missing identifiers (e.g. OCLC, doi etc) which are useful.Is there a citation for Rigel was also known as Gin-waki, (銀脇), etc?
That has been in article for many years unsourced - I could not find a source so removed now Cas Liber (talk · contribs) 13:28, 4 April 2020 (UTC)

The sentence "Jauzah" was a proper name of the Orion figure, an alternative Arabic name was رجل الجبار riǧl al-ǧabbār, "the foot of the great one" conveys much technical info; suggest a tweak. Perhaps, "Jauzah" was a proper name for Orion; an alternative Arabic name was رجل الجبار riǧl al-ǧabbār, or "the foot of the great one", from which stems the rarely used variants Algebar or Elgebar.

I don't get With constellation representing...; should it be Within the constellation representing...? Also, maybe describe and link Orion on first use.

much of our understanding about their characteristics; not sure about the first person—how about much of what scholars understand about their characteristics or something.

ts energy output is poorly known--->can only be estimated.

Mind you, I guess these can only really be suggestions on my part, as I may unintentionally be altering the substance by adjusting the prose. ——SN54129 12:56, 3 April 2020 (UTC)

All the prose changes you've suggested are good and have been used, though and pausing on the last one as everything with stars is estimated/calculated anyway. Need to think about that one. Cas Liber (talk · contribs) 21:26, 3 April 2020 (UTC)
The uncertainty in many of the values given in this article would astonish most people. Some of them can be seen in the ± figures in the starbox, and remember those are only one sigma ranges, so the "true" value is almost as likely to be outside the range as inside it. Astronomical error ranges also typically only capture a small subset of the possible errors, for example the statistical errors of a set of observations but ignoring any underlying or systematic errors. We need to avoid being too dogmatic about most of the claims for physical properties, distance, etc. Equally, I can see that having too many "estimated" and "about" words littering the article can be distracting. Call out anywhere you think the balance is wrong.Lithopsian (talk) 14:17, 6 April 2020 (UTC)
I wrote that about the representation here during the GA review, although I don't see anything in the review to prompt it. I wasn't entirely happy with it at the time, but I couldn't come up with anything better. Maybe go back to the original version? Lithopsian (talk) 20:14, 5 April 2020 (UTC)


Some comments from Sam-2727:
  • supergiant primary component A of the Rigel system. Sounds kind of awkward. Is "the primary component of the Rigel system" not specific enough?
fair point, removed Cas Liber (talk · contribs) 13:48, 5 April 2020 (UTC)
  • then ordered the stars within each class according to a different scheme. Did his scheme vary from constellation to constellation? I assume this is the case, but it is never mentioned in the article.
yes - sometimes the order appears random, sometimes from one end of the constllation to the other (such as the Big Dipper). I thought it was too off-topic to go into more detail Cas Liber (talk · contribs) 13:48, 5 April 2020 (UTC)
  • the exception is the area north of the 82nd parallel north. For clarification, could be "the exception being the part of the Arctic Ocean north of the 82nd parallel north.
err...and some of Greenland and Ellesmere Island..... Cas Liber (talk · contribs) 13:48, 5 April 2020 (UTC)
Fair, but the rest of that sentence is only referring to oceans. Sam-2727 (talk) 03:08, 6 April 2020 (UTC)
  • source 25 doesn't support the claim that It is usually fainter than Capella. All the source says on this that I can find is that Capella "ever-so-slightly exceeds Rigel in brightness." I.e. there isn't a modifier (usually) in this statement.
fair point, qualifier removed Cas Liber (talk · contribs) 13:48, 5 April 2020 (UTC)
  • The unusual Hα line profile is observed to vary unpredictably...rarely there is a pure emission Hα line. Does this really have to be one massive sentence? I would take out the colon (replacing it with a period), and split the rest up into sentences that flow better.
split Cas Liber (talk · contribs) 13:50, 5 April 2020 (UTC)
  • the Alpha Cygni class of variable stars, defined as.... Defined by who? Also, that quote isn't coming from the citation provided. I believe it's originally coming form the AAVSO: .
The quote comes from the given citation, the General Catalogue of Variable Stars (see ). Where do you think the AAVSO copied it from? So, defined by them. Should it say explicitly that's who defined it? They didn't strictly make the definition, but they did write it down in exactly those words. Lithopsian (talk) 19:35, 5 April 2020 (UTC)
Makes sense. The only thing is, the source currently in the article, , doesn't include that wording. So maybe change that source to the one you've provided. Sam-2727 (talk) 03:08, 6 April 2020 (UTC)
Later comment: The source you provided also doesn't contain the words in that quote. Sam-2727 (talk) 03:18, 6 April 2020 (UTC)
yes it does - they are abbreviated to "ACYG" (sentence occurs in para after first hit of "ACYG" using cntrl- F Cas Liber (talk · contribs) 13:17, 6 April 2020 (UTC)
  • The 'e' indicates that it displays emission lines in its spectrum, while the 'p'.... This assumes that these have already been mentioned in the article, but I can't find reference to these designations anywhere else.
The description is referring to the "Bep–AepIa" spectral type range quoted in the previous sentence. Describe in more detail? Reword to be clear what is being described? Drop completely? Seems like a random collection of letters that deserves some explanation for non-astronomers. Lithopsian (talk) 19:41, 5 April 2020 (UTC)
  • Rigel mass-loss rate due to stellar wind. Should be: "Rigel's mass-loss rate".
Done. Lithopsian (talk) 19:42, 5 April 2020 (UTC)
  • It is estimated that Rigel has lost around 3 solar masses (M☉) since beginning life as a star of 24±3 M☉ 7 to 9 million years ago. The citation given does give the original mass estimate, but doesn't mention Rigel losing 3 SM in its lifetime.
The paper describes that evolutionary models predict an initial mass of 24 and a current mass of 21 (both subject to a margin of error of 3 M☉). We could just state those two numbers, but it seems cruel to force people to do their own arithmetic and the section is called "Mass loss" after all. Lithopsian (talk) 19:49, 5 April 2020 (UTC)
  • However, the measurements for this object may be unreliable, possibly because it is a close double star. This and the proceeding sentence at the moment aren't exactly supported by the citation given which only mentions the general limitations with respect to binary stars, not in the case of Rigel's companion star (which isn't mentioned explicitly in the source anywhere).
I removed any mention of why the value might be unreliable (there are many reasons), only that it might be (as indicated by excess astrometric noise, for example). Lithopsian (talk) 19:56, 5 April 2020 (UTC)
  • or a distance of 39 light-years (12 parsecs) away. Again not supported by the current citation. I'm also skeptical how if the distance to Rigel is unknown, the distance from it to a nebula can be known so precisely.
We don't know how far it is from the nebula, although there is circumstantial evidence that it is "not far". The distance of 12 pc is *only* the projected distance, ignoring any difference in the distances of each object from us. I added the word "projected". Lithopsian (talk) 19:59, 5 April 2020 (UTC)
I stopped at "Stellar System." Might have time to get through that tomorrow. Sam-2727 (talk) 05:36, 5 April 2020 (UTC)
Continuing:
  • suspected Rigel B to be double "to be a binary system." It's just as easy to understand, and "double" sounds pretty colloquial, in my opinion. Sam-2727 (talk) 03:08, 6 April 2020 (UTC)
changed Cas Liber (talk · contribs)
  • Support I haven't had the time to go through the full article, but everything in the criteria seems to be addressed and only thing I'm finding in the comments above are ultra-minor copyediting changes (that no one will notice anyway...). Sam-2727 (talk) 03:28, 9 April 2020 (UTC)
thanks! all input appreciated... Cas Liber (talk · contribs) 07:48, 10 April 2020 (UTC)
  • Comments from Hawkeye7
    I'm not an astronomer, so perhaps not surprising that I found the Physical characteristics section confusing.
    Yep - trying to balance accessibility and accuracy is a...challenge Cas Liber (talk · contribs) 04:00, 6 April 2020 (UTC)
    • Rigel is a blue supergiant that has exhausted the hydrogen fuel in its core First of all, the term "blue supergiant", linked here, is actually used in the first sentence of the section. Suggest moving this paragraph (and possibly the next) up to the beginning of the section.
      Yes that is good - moving the para that describes /what/ it is up now done Cas Liber (talk · contribs) 04:00, 6 April 2020 (UTC)
    • In this section, "Rigel" refers to "Rigel A", right?
      Yes Cas Liber (talk · contribs) 04:00, 6 April 2020 (UTC)
    • Having exhausted the hydrogen fuel in its core, I take it that it this means that it its burning hydrogen in the outer shell? I'm guessing this because it says later that "Recent stellar evolution models suggest the pulsations are powered by nuclear reactions in a hydrogen-burning shell that is at least partially non-convective. The star may also be fusing helium in its core." (That sentence would be better placed here.) I deduce that this is because the pressure is not great enough for helium fusion, which requites much higher temperature than hydrogen fusion? Or it is that the core is too clogged with heavier elements?
      I have moved that up so discussion of what elements are burning where are near each other Cas Liber (talk · contribs) 10:45, 6 April 2020 (UTC)
    • When it was on the main sequence, its temperature would have been around 30,000 K This is the surface temperature, right?
      yes/added Cas Liber (talk · contribs) 04:00, 6 April 2020 (UTC)
    • Consider linking Ledoux criterion.
      done Cas Liber (talk · contribs) 04:00, 6 April 2020 (UTC)
    • Consider moving the footnotes in the infobox to after the units.
      That would be tricky. The infobox contents are largely formatted by a series of starbox templates. They take, for example a number and a reference as input, and add the appropriate units. Making the template understand which piece of text is the value and which is the reference would be possible, but is not a trivial change. It would seem to be outside of the scope of this article, and would need project-level discussion since it would affect every star article. Lithopsian (talk) 14:08, 6 April 2020 (UTC)
      I asked you to consider it, and you did, so that it fine. Support promotion to featured status. Hawkeye7 (discuss) 21:49, 6 April 2020 (UTC)
thx! Cas Liber (talk · contribs) 00:14, 7 April 2020 (UTC)

Comments from HaEr48 (support)

Well written and referenced. Much of it can be understood with university-level knowledge plus some effort, so nicely done. I understand the difficulty of making articles like this accessible without dumbing down too much, so I try to focus my review on improving accessibility (in addition to other stuff). That said, I'm no expert so if my suggestions are way off feel free to push back.

  • Note, I intend to claim this review for Wikicup.
  • of spectral type B8Ia: any link for "spectral type" or "B8Ia"?
Spectral type wikilinked. There isn't a particularly good page to link B8Ia to, although it is explained more in the body. Lithopsian (talk) 20:14, 18 April 2020 (UTC)
  • of the first class: link or briefly explain what "first class" signifies in this sentence?
The class is described in the previous sentence. I added the word magnitude to try and make this clearer. Lithopsian (talk) 20:14, 18 April 2020 (UTC)
  • Rigel is a prominent equatorial navigation star: I think the passage that follows does a good job of explaining why it's a good navigational star, but not why it's an equatorial navigation star. Is it possible to explain more about what links it to the equator, e.g. "Rigel is a prominent equatorial navigation star because of its location in …, and because it is readily visible in all the world's oceans"?
    @Casliber: I'm still wondering about this. Any idea? HaEr48 (talk) 12:30, 26 April 2020 (UTC)
I'll have a go at this. Since the linked article has a section on equatorial navigation stars, and Rigel is one of them, I've piped the whole phrase "equatorial navigation star" to that section. Lithopsian (talk) 19:06, 26 April 2020 (UTC)
  • the radial velocity of Rigel.. was seen to vary. Can we clarify, for the uninitiated, radial velocity with respect to what?
Added helioentric. Lithopsian (talk) 20:14, 18 April 2020 (UTC)
  • In 1933, the Hα spectral line was seen to be unusually weak and shifted 0.1 nm towards shorter wavelengths: Would it be appropriate to say "In 1933, the Hα spectral line of Rigel", for clarity?
I used a slightly different form of words to make it explicit which Hα is being referred to. Lithopsian (talk) 20:30, 18 April 2020 (UTC)
  • In those spectral types, the 'e' indicates that it displays emission lines in its spectrum, while the 'p' means it has an unspecified spectral peculiarity.: Trying to understand these 'e' and 'p' reference, have the article mentioned them before?
"Bep–AepIa" in the previous sentence. "In those spectral types" was recently added to try and clarify what was being talked about in this sentence. Obviously not 100% successful, but I'm not sure how to make it clearer. Lithopsian (talk) 20:23, 18 April 2020 (UTC)
Ah I see, I think it's easy to miss because it reads like a combination of two names "Bep" and "Aepla" and the individual characters aren't meaningful. Suggest bolding the relevant characters, e.g. "The 'e' and 'p' in Bep–AepIa indicate ..."
I think the letters and acronym are pretty close together in consecutive sentences as is - worried it will look repetitive or like we're labouring the point otherwise.... Cas Liber (talk · contribs) 14:19, 20 April 2020 (UTC)
Done. Lithopsian (talk) 20:28, 18 April 2020 (UTC)
  • The 2007 Hipparcos reduction of Rigel's parallax: link reduction (or explain what it means in this context) and parallax? And better yet if there's a link that explains how the parallax can be used to estimate distance.
Added two wikilinks. Lithopsian (talk) 20:40, 18 April 2020 (UTC)
The first instance is linked, near the start of the section Distance. Perhaps it needs to be spelled out? Lithopsian (talk) 20:18, 18 April 2020 (UTC)
Indeed I missed that. Suggest spelling out the first mention. HaEr48 (talk) 21:02, 18 April 2020 (UTC)
  • I'm trying to reconcile "Since its discovery, there has been no sign of orbital motion" and "The pair would have an estimated orbital period of around 24,000 years" Can you clarify what the latter signifies if there is no orbital motion?
Kepler's Law. The two stars cannot simply be sailing along next to eachother. Either they are gravitationally bound (ie. in orbit) or they are not and will separate indefinitely. Assuming they are bound, and making a few other assumptions such as the size of the orbit and the masses of the stars, the period of the orbit can be calculated. Take it is an educated guess, since the masses are not known precisely and the actual semi-major axis will vary depending on the eccentricity of the orbit. That's what the ref has done. When orbital motion can be observed, the eccentricity and the masses can be calculated and the orbit defined more precisely. Lithopsian (talk) 13:55, 20 April 2020 (UTC)
  • "a companion star to Rigel" can we name the companion as well?
It's Rigel B. I'll say so in the article. Lithopsian (talk) 13:55, 20 April 2020 (UTC)
  • with the note, et dicitur Algebar. Nominatur etiam Rigel: can we translate this note?
@Lithopsian: anyone knows the translation of this note? HaEr48 (talk) 02:15, 24 April 2020 (UTC)
yes it means, "...and it is called Algebar. It is also named Rigel". I was going to add but paused and then got distracted. Will add now. Possibly a bit repetitive. Would it be better as a footnote? Cas Liber (talk · contribs) 03:41, 24 April 2020 (UTC)
I see what you mean. Your call: I think we can either make it a footnote, or just remove the Latin, or reword somehow to remove repetition. But I think it's not preferable to leave an untranslated phrase and leave our readers confused as to what it means. HaEr48 (talk) 01:33, 25 April 2020 (UTC)
okay I footnoted the translated segment Cas Liber (talk · contribs) 06:11, 26 April 2020 (UTC)
  • Per WP:REFER, we should avoid a lead sentence like "is the name applied to a star system". Is the scope of the article about the star system, or just the star?
This is a problem with most notable stars that are actually multiple star systems. The name applies to the star system (with components called 'A', 'B', 'C' etc. But component A is often treated as the primary topic and just called Rigel (Sirius is another example, no-one calls it Sirius A unless they are also talking about Sirius B in the same context. To complicate things the new naming rules that came out in 2016 stuck the name on the primary components..so since 2016 the main component is 'Rigel' not 'Rigel A'..but the term is widely applied to the star system...sigh. Also - 99.75% of the light from the single dot of light in the sky is from the brightest component. I wish it were simpler but here we are, and we've tried to reflect the ambiguity in nomenclature as simply and clearly as posslbe Cas Liber (talk · contribs) 05:18, 20 April 2020 (UTC)
I don't like the "... is the name ..." format of the opening sentence. The article is primarily about the star - or the star system - not about the name, so we should say something like "Rigel is a star ...". Lithopsian (talk) 13:55, 20 April 2020 (UTC)
I am not thrilled by it either but struck me as the most succinct and accurate way to get the point across about what it means. Happy to rethink this. Cas Liber (talk · contribs) 14:25, 20 April 2020 (UTC)
@Lithopsian and Casliber: How about something like "Rigel ... is a star system in the constellation of Orion, whose brightest star is also known by the same name"? Also, if almost all the visible light from earth comes from the primary star (99.75% as you said), I believe it's worth mentioning in the article e.g. in Observation, if not in the lead itself. HaEr48 (talk) 13:43, 21 April 2020 (UTC)
I'd like to reverse it, and even caveat it a little despite being the opening sentence. Along the lines of "Rigel is a star ... " - so far, so good, I don't think anyone can argue with that - " ... , and colloquially also the name of the whole star system with Rigel as its primary." I know, the second section is not succinct enough. Also, there might be a better word than colloquially. Lithopsian (talk) 19:01, 21 April 2020 (UTC)
suggest "broadly" for "colloquially" (heh, opposite of "strictly" sensu lato would be the term if this were a biology article) Cas Liber (talk · contribs) 21:50, 21 April 2020 (UTC)
Going back to fundamentals: "Rigel is a star ..." seems uncontroversial, referring either to a huge ball of plasma or to a dot in the night sky, but is "Rigel is a star system ..." correct in any way? We discuss Rigel's companions, gravitationally-bound or otherwise, in the article, and they are often referred to as Rigel B, etc., but the bald statement that "Rigel is a star system" doesn't seem to make any sense to me. On that assumption, can we not just say "Rigel is a star" as we used to and then feel free to describe its companions being careful not to call the star system as a whole Rigel. Lithopsian (talk) 20:11, 22 April 2020 (UTC)
@Lithopsian: I'm fine with that too. I thought we were going with defining as the star system due to the current wording of the lead, but if "Rigel is a star ... " makes more sense, let's go with it. HaEr48 (talk) 12:39, 23 April 2020 (UTC)
I just realised that the IAU in 2016 shifted usage towards the star alone in the system. I have rewritten it thus. It has now struck me as the IAU has specified the name to the star (and not the system) that this simplifies things alot. Question is, do we need to put a note in the lead that the name can be broadly construed to desginate the system as a whole..or just leave it. Cas Liber (talk · contribs) 14:24, 23 April 2020 (UTC)
I like this version. It says that Rigel is a star. It also says that there is an associated star system. I think in the rest of the article we refer to the "Rigel system", but don't explicitly call it simply "Rigel". Hopefully this isn't confusing any more. Lithopsian (talk) 15:02, 23 April 2020 (UTC)
@Casliber: IMO, It can be part of the second sentence "It is also the brightest and most massive component of a star system known by the same name ..." or something similar. Also suggest adding some clarification, as well as the fact that the whole system appears as a single dot, with nearly all light coming from the main star, in the article body. But I like your lead change. HaEr48 (talk) 15:05, 23 April 2020 (UTC)
I tweaked it thus. Cas Liber (talk · contribs) 06:25, 26 April 2020 (UTC)
I think we have a winner. Lithopsian (talk) 19:07, 26 April 2020 (UTC)
  • I'm no expert so feel free to disagree with me on this. I'm trying to judge comprehensiveness by comparing with another FA for Betelgeuse, it has significantly more detail including motion/kinematics, mass loss, a section of "circumstellar dynamics", as well as its life phase. Is there any reason why this article has much less details on those?
There is alot more published material on Betelgeuse concerning such issues as mass loss (and other areas), hence that article has alot more data from reliable sources to draw on to produce and article. To a large degree, article size reflects the amount of published material there is to draw on. Cas Liber (talk · contribs) 21:11, 19 April 2020 (UTC)
We are perhaps a little short on information about the evolution of Rigel. I think some text was lost during arguments last year. I'll try to add a section on this, especially since we mention in the lead that it is going to explode as a supernova. Quite the tease when we don't explain that better. Lithopsian (talk) 14:01, 20 April 2020 (UTC)

Thank you for working on this article, I learned a lot from reading it. HaEr48 (talk) 19:30, 18 April 2020 (UTC)

Support, although would be happy if more info can be added about evolution, as Lithopsian mentioned. Thank you for this article! HaEr48 (talk) 00:08, 27 April 2020 (UTC)
thanks for that, and in progress Cas Liber (talk · contribs) 00:24, 27 April 2020 (UTC)

Comments from Fowler&fowler

  • I should know better than to make promises, even qualified ones. But broken promises don't take away from the fondness I have always had for this constellation and for this star. I'm reserving a slot, and will probably make a few comments now, and return later, and intermittently, for others. (Note: I haven't read the previous reviewers' comments.)
  • "is the name applied to a star system—or strictly to the system's brightest star—in the constellation of Orion.
  • "strictly," i.e. "with the exact use of words," has the effect of narrowing a word's application. Logically, I think, it accompanies an "and" not an "or," for the sentence is equivalent in meaning to the two independent clauses: "... is the name applied to a star system; strictly/when narrowed/with the exact use of words, it applies to the system's brightest star." So, would it be be clearer to write:
  • "... is the name applied to a star system in the constellation of Orion, and strictly to the system's brightest star." (that way there are no breaks in the middle of the general definition either which may distract the reader.)
aawwww, I liked my mdashes..."or" sounds more "natural" to me but the logic of "and" makes sense. Duly changed Cas Liber (talk · contribs) 05:07, 20 April 2020 (UTC)
Sorry about the m-dashes. :( I like them too, but prefer them generally for explication, emphasis, clarification, or determinedly purposeful meandering. As two m-dashes are a form of parenthesizing, what they enclose is generally of less semantic value than the main clause. In this instance, though, we seem to be emphasizing both interpretations—the system and the star—equally. If that is not the case, please let me know, and we can go back to your version, or rephrase it again. As for "or vs. and," I haven't checked, but I would imagine "or" to be more common in speech or casual writing, but "and" with "strictly (speaking) to be favored in books." Fowler&fowler«Talk» 02:17, 22 April 2020 (UTC)
There are also the eternal WP pieties—and perhaps of other encyclopedias as well—about naming and being. But shortening it to "... is a star system in the constellation of Orion, and strictly the system's brightest star" is meaningless as "strictly (speaking)" is about speech, names, and expressions, not about existence. Fowler&fowler«Talk» 02:32, 22 April 2020 (UTC)
Britannica avoids the naming/being dilemma with: "Rigel, also called Beta Orionis,(is) one of the brightest stars in the sky, intrinsically as well as in appearance. A blue-white supergiant in the constellation Orion, Rigel is about 870 light-years from the Sun and is about 47,000 times as luminous. A companion double star, also bluish white, is of the sixth magnitude." In other words, they avoid the collective name. Fowler&fowler«Talk» 04:44, 22 April 2020 (UTC)
We used to do exactly the same, describe it as a star without being too precise (at least in the lead) about whether that is a single ball of plasma or several in a gravitationally bound system. It was suggested that this was confusing when later we start referring to a system of four stars with names such as Rigel B. I'm happy to go back to the simpler definition and leave the details in the body. Lithopsian (talk) 17:03, 22 April 2020 (UTC)

Yeah. Damned if you do ... I see the problem, though I personally don't mind the naming/referring beginnings. In my youth on Misplaced Pages, I even created quite a few. But they fell victim to the-whatnots-that-be. As you have already made the change once, you could let it remain until the evidence of opposition becomes overwhelming. After all Rigel is a name for a complicated reality. Even if we reduce the scope of the name's reference, as Britannica does, it is still a name. However, one approach for avoiding naming/referring but still preserving the complexity could be a slightly more prosaic opening

"The star system named Rigel ... etc ... lies in the constellation of Orion, and appears as a single blue-white point of light to the naked eye; the system contains at least four stars, the principal star of which, named Rigel or Rigel A, is a massive blue supergiant of spectral type B8Ia."

I'm throwing this out there as another possibility, one possibly attracting fewer objections. Fowler&fowler«Talk» 20:40, 22 April 2020 (UTC)
  • "Appearing as a single blue-white point of light to the naked eye, the system contains at least four stars, the primary star of which (either Rigel A or simply Rigel) is a massive blue supergiant of spectral type B8Ia."
I have rewritten it thus. I just realised that the IAU has pushed for the name to refer to the star and not the system, although the system is broadly known as the Rigel system or abbreviated to Rigel (sort of). Question is, is it worth adding somewhere that the system can be called 'Rigel' (though come to think of it, I don't know that any source specifically says that) or the Rigel system or if that is just obvious then leave it Cas Liber (talk · contribs) 14:41, 23 April 2020 (UTC)
  • Nicely written.
  • do you need "either" and the parenthesis? (See more below.)
I dropped the parenthetical. This is the lead, no need for caveats everywhere so king as it is explained fully in the body. Lithopsian (talk) 20:22, 19 April 2020 (UTC)
OK Thanks. Fowler&fowler«Talk» 04:22, 22 April 2020 (UTC)
  • I'm not good at punctuation, but is there a comma before "or simply Rigel?"
segment removed so moot Cas Liber (talk · contribs) 05:08, 20 April 2020 (UTC)
  • Is "primary star" meant in an astronomical sense, such as primary (astronomy) (i.e. the star is massive enough to constitute the approximate center of mass of the four-body system)? If so, would it be better to break it up as:
  • "Appearing as a single blue-white point of light to the naked eye, the system contains at least four stars; the primary, Rigel A, or simply Rigel, is a massive blue supergiant of spectral type B8Ia?"
Yikes! Please don't link to that article, its awful as well as inaccurate. "Primary" in the context of a binary star system refers to the brighter, or occasionally the more massive, of a pair. It need not be massive enough to constitute the approximate centre of gravity of the system, and in most cases it won't. Lithopsian (talk) 20:17, 19 April 2020 (UTC)
OK Thanks. Fowler&fowler«Talk» 04:22, 22 April 2020 (UTC)
  • If, on the other hand, "primary" is meant in the ordinary meaning of "principal or chief," then would it be better to say:
  • "Appearing as a single blue-white point of light to the naked eye, the system contains at least four stars, the principal one of which—Rigel A, or simply Rigel—is a massive blue supergiant of spectral type B8Ia?"
I changed it to "principal" even though "primary" does have a specific meaning in this context. Lithopsian (talk) 20:22, 19 April 2020 (UTC)
OK Thanks. Fowler&fowler«Talk» 02:19, 22 April 2020 (UTC)
You'd think so wouldn't you. However, this particular spectral type does implicitly mean an MK spectral type which is discussed in the Modern classification section (of the same article), or even in the Yerkes spectral classification sub-section. Lithopsian (talk) 20:30, 19 April 2020 (UTC)
Too many links all to essentially the same place? That particular section isn't very illuminating about the B8Ia spectral class. Blue supergiant might be more informative, already linked. Lithopsian (talk) 20:30, 19 April 2020 (UTC)
OK Thanks. Fowler&fowler«Talk» 04:22, 22 April 2020 (UTC)
  • It is calculated to be anywhere from 61,500 to 363,000 times as luminous and 18 to 24 times as massive as the Sun, depending on the method used to calculate its properties and assumptions about its distance, estimated to be about 860 light-years (260 pc).
  • Is "massive" meant in its astronomical meaning of "having great mass?" If so, should it be linked to mass (and not, were we in the business of linking, to massive star, which doesn't quite pin down the meaning of "massive")? I.e. would it be better to rewrite: "It is calculated to be anywhere from 61,500 to 363,000 times as luminous as the sun, and 18 to 24 times as massive?"
"Massive" is linked in the previous sentence to massive star although this is somewhat tautological since we say it is a supergiant. If any link is to be made in the sentence about the actual mass, it should probably be to solar mass since we are using that in a rather colloquial way as a unit. I made this change, with your form of words. Lithopsian (talk) 20:41, 19 April 2020 (UTC)
OK Thanks. Fowler&fowler«Talk» 04:22, 22 April 2020 (UTC)
  • "depending on the method used to calculate its properties and assumptions about its distance, estimated to be about 860 light-years (260 pc)."
  • "depending ... distance" is too vague, too generic, to convey any meaning. My thought is: either make it more precise with more information in a separate sentence or get rid of it.
  • "estimated to be about 860 light-years (260 pc)." This is confusing. Apparently, the assumptions about the distance computation are varied, but the distance is not.
  • What is not clear here is this: The luminosity and mass estimates have wide ranges depending on the assumptions about distance. Then why is the distance also not dependent on these assumptions, and estimated in a range? Fowler&fowler«Talk» 04:30, 22 April 2020 (UTC)
Perhaps drop "why" there is a range of estimated physical properties from the lead, and just state the estimated distance on its own? There's a whole section about the distance and "about 860 light years", where "about" papers over a lot of cracks, is probably simplest and safest for the lead. Lithopsian (talk) 17:10, 22 April 2020 (UTC)
  • "Its radius is over 70 times that of the Sun, and its surface temperature is 12,100 K."
  • If this is a comparison with the sun, then the surface temperatures should be compared as well. Besides, we were comparing the physical dimensions earlier, so why did we leave out the radius from the previous sentence?
The previous sentence ran on far too much already, although that should probably be fixed. Solar mass M☉, solar radius R☉, and solar luminosity L☉ are defined astronomical units. Solar temperature is not. Partly because defining a temperature as a multiple of another temperature gets into sticky territory in terms of the physics. Let's just say it isn't done and we probably shouldn't set a precedent here. Lithopsian (talk) 20:49, 19 April 2020 (UTC)
I see. OK Thanks. I do think you should split the previous sentence for easier comprehension. Fowler&fowler«Talk» 04:22, 22 April 2020 (UTC)
I have dropped the distance piece from that sentence, and moved a simple statement of (approximate) distance into the opening sentence, which has been conveniently shortened in other edits. Lithopsian (talk) 20:13, 23 April 2020 (UTC)
  • Another thing to note is that the elementary volume formula, 4/3 times pi times radius cube, suggests that all things being equal, the mass of Rigel should be 70 x 70 x 70, i.e. 343,000 times that of the sun; but it is only 18 to 24 times in mass. Is this is linked to burning out most of its fuel and expanding? Either way, should the:
  • luminosity and temperature be in one sentence (as well as the comparison of the latter with the sun)?
  • and the radius and the mass be in another sentence?
There is a case to be made for different groupings, but there is nothing particularly special about these pairings. See below. Lithopsian (talk) 21:01, 19 April 2020 (UTC)
  • Are there sources that would support a statement such as: "Although Rigel's radius is 70 times that of the sun, its mass is only between 18 and 24 the sun's (or "that of the sun.")? If so, such a sentence would be more meaningful.
  • " Rigel varies slightly in brightness, with apparent magnitude ranging from 0.05 to 0.18."
  • Are there sources that would support: "Rigel varies only slightly in brightness?" If so, the addition of "only" will help the reader later when Betelguese is mentioned.
I've had a stab at this, as well as the next point. I didn't use the word "only", "slightly" seemed quite subjective enough, but still tried to clarify that Betelgeuse is the one doing most of the varying. Then reversed the explanation of the variability type classification, and the causes of the variation. Perhaps too wordy - I made room by breaking out a paragraph, but could still be too much detail for the lead. Can't win really. Lithopsian (talk) 19:16, 21 April 2020 (UTC)
I agree that the inclusion of "slightly" is important as it varies in brightness much less than other notable variables Cas Liber (talk · contribs) 23:39, 21 April 2020 (UTC)
OK Thanks. Fowler&fowler«Talk» 04:22, 22 April 2020 (UTC)
"slightly" included now Cas Liber (talk · contribs) 11:41, 28 April 2020 (UTC)
  • "Its intrinsic variability is caused by pulsations, and it is classified as an Alpha Cygni variable."
  • This is not very transparent to a novice such as I. Would it be clearer if we write: "Its intrinsic variability is caused by pulsations that vary inconsistently over its surface area, causing it to be classified as an Alpha Cygni variable?" (or somesuch?)
The pulsations are non-radial, but not inconsistent. For example, the poles may be shrinking while the equator is expanding but they may be doing it "in sync". It might help to know what is not very transparent. Do you want it to be clearer why Rigel is classified as an Alpha Cygni variable? The answer might not be very satisfying, basically that hot luminous supergiants that vary by not-large amounts with not-well-defined short-ish periods are classified as Alpha Cygni variables. The physical explanation for their variability can then be investigated, with the hope that the stars in the class are all actually doing similar things for the same reason. Lithopsian (talk) 21:12, 19 April 2020 (UTC)
OK Thanks. Fowler&fowler«Talk» 04:22, 22 April 2020 (UTC)
  • "Rigel is generally the seventh-brightest star in the night sky and the brightest star in Orion, though it is occasionally outshone by (more variable) Betelgeuse."
  • Nice sentence!
  • Why the parentheses?
  • It should probably be "the more variable Betelguese."
I've changed to this wording, although I'm not convinced it is ideal. I didn't like the parentheses so at least they're gone. Lithopsian (talk) 20:52, 19 April 2020 (UTC)
OK Thanks. Fowler&fowler«Talk» 04:22, 22 April 2020 (UTC)
  • "Rigel's mass-loss due to its stellar wind is estimated be around 10 million times more than that of the Sun."
  • :) Aha. So this explains the abnormally low mass. Which means: would it lend greater coherence to the paragraph if the sentences are reshuffled so as to combine the semantically related ones, e.g. something like:
  • "Rigel's radius is more than 70 times that of the sun; its mass is 18 to 24 times greater. Its mass-loss due to its stellar wind is estimated be around 10 million times that of the sun?"
No, this doesn't explain the low mass. Stellar densities vary. Even amongst main sequence stars, stars more massive than the sun are less dense and hence disproportionately large in radius. But mostly, Rigel is a supergiant, hence even larger in comparison to its mass. In general, the radius of a star is not highly correlated with its mass. Lithopsian (talk) 21:01, 19 April 2020 (UTC)
These two sentences are now together. I removed the piece between them, about variability, into a separate paragraph. Lithopsian (talk) 19:18, 21 April 2020 (UTC)
OK. I like the new paragraph Thanks. Fowler&fowler«Talk» 04:22, 22 April 2020 (UTC)
"Lucida que est in pede sinistro: et est communis ei et aquae: et dicitur Algebar nominatur etiam Rigel," translated as, "Bright which is in the left foot and is common to him and the water and called Algebar (is) named also Rigel." The water here is the constellation Eridanus, seen both in the picture as the river of Hades and in the sky as the constellation at the foot of Orion
The constellation Eridanus which borders Orion
  • "Estimated to be around 7 to 9 million years old, it has exhausted its core hydrogen fuel, expanded and cooled to become a supergiant, and will end its life as a type II supernova."
  • Nicely written.
  • More later. Looking forward! Fowler&fowler«Talk» 21:27, 18 April 2020 (UTC)
  • The lead looks good now. I won't have time to go through all the sections, but will take a good look at: Nomenclature, Distance, Stellar System and Etymology, starting with the last. The stellar system reminds me that you guys should work on taking Kepler's laws to FAC. The beautiful derivation by Newton was one of the highlights of my sophomore mechanics course in college. Fowler&fowler«Talk» 11:46, 24 April 2020 (UTC)
Etymology
  • "al-jabbaar" (The mighty one) seems to be Orion. See B, or perhaps in Arabic accounts, he was visualized as A, judging from what follows. The Latin, which I now only infirmly remember, seems to be from this book, page 158 and 159, or some earlier version of which this is a verbatim copy. It begins with "Stars of Orion ..." Number 2 is "Bright (lucido) which is in the right (dextrum) shoulder (humerus) is called Betelguese" Number 35 on the next page is: "Bright (lucido) which is in the left (sinistro) foot (pedo) ... and called Algebar named also Rigel." The "..." part—which is probably a reference to The Odyssey and to Odysseus seeing a shadow of Orion in the water, or the underworld—can be left out. It is your call, but I think adding some version of the image A and reference to "bright which is in the left foot" in addition to what you already have, might be more motivating for a reader. (A is preferable to B, because the reference is to the foot, not leg or knee). It is your burden, of course, to find a modern citation. Fowler&fowler«Talk» 12:37, 24 April 2020 (UTC)
  • I found the full quote from the Alfonsine tables. It is, "Lucida que est in pede sinistro: et est communis ei et aquae: et dicitur Algebar nominatur etiam Rigel," translated as, "Bright which is in the left foot and is common to him and the water and called Algebar (is) named also Rigel." The reference to water is to the constellation Eridanus, which lies at the "foot" of Orion, but is also a river in mythology. The citation is to Allen, Richard H. (2013) , Star Names: Their Lore and Meaning, Dover Inc., p. 312, ISBN 978-0-486-13766-7 {{citation}}: Cite has empty unknown parameter: |1= (help) Fowler&fowler«Talk» 04:10, 25 April 2020 (UTC)
  • @Lithopsian, Attic Salt, and Casliber: I'm sorry but can we have some order in the review process here? Is the previous editor done with his or her edits? If not, why is s/he not discussing the proposed edits here? We can't just randomly add an illustration, File:Kitāb suwar al-kawākib al-ṯābita, Orion, BnF-Arabe-5036-193v.jpg, from a 15th century copy transcription of the Book of Fixed Stars (whose various versions typically have two illustrations, the view from the earth, and its mirror-image in the celestial globe, which is viewed with a mirror). The labeling moreover has an error. The label is rendered by the calligrapher "al-hausa," not "al-jausa." Missing a nuqta (or diacritics dot) below changes jauza to hauza; it maybe that in some form of medieval Arabic the nuqta was dropped in this context, or the calligrapher attached it somewhere else, where it is not readily visible, or maybe it was called al-hauza then or in that region, but we can't have these kinds of confusing undiscussed additions. And it is confusing for a reader when the illustrations suddenly changes to a mirror image, and despite that the caption says "left foot.' If an illustration from the Book of Fixed Stars is needed, there are better versions which are not missing the nuqta either, from this version dated 1009-10 AD (Bodleian Library, Oxford, manuscript Marsh 144), which has both views: the the regular view from earth, and the mirror image in the celestial globe, but with separate illustration which is much older, transcribed 23 years after the death of the author, the Persian astronomer, Abd al-Rahman al-Sufi, most likely by the author's son (see here). I still think that the illustration above has a much better fit with the Latin. Mainly though, I would prefer the edits to be discussed here; otherwise, what is the point of us making comments? Fowler&fowler«Talk» 13:50, 25 April 2020 (UTC)
I can't control where people post queries and it is challenging going back and forth between two reviewers. I find the colour coding helps. I meant to get to outstanding items yesterday but was sidelined with (many) RL chores. I will try to see what is redulicated between reviewers and note. Hang on a sec. Cas Liber (talk · contribs) 22:34, 25 April 2020 (UTC)

I'm happy to hold off until s/he is done. Removed all my orange now. Fowler&fowler«Talk» 23:52, 25 April 2020 (UTC)

ok I have answered the last two of Ha Er's queries, and waiting to see if they are satisified. Cas Liber (talk · contribs) 06:28, 26 April 2020 (UTC)
Ha Er is now satisfied so all outstanding issues are within this section Cas Liber (talk · contribs) 11:17, 27 April 2020 (UTC)
{{font color|blue|
Back to the image - @Fowler&fowler:, happy to go with the older one - which one would you suggest - the reversed one or the one the right-way-round? Cas Liber (talk · contribs) 14:14, 27 April 2020 (UTC)
If the source contains an image that isn't reversed, and there is nothing that is being demonstrated by having the image reversed, then I'd say use the one that conforms to modern expectations. Lithopsian (talk) 14:30, 27 April 2020 (UTC)
Sure. The citation would be to Casagrande-Kim, Roberta; Thrope, Samuel; Ukeles, Raquel (2018), Romance and Reason: Islamic Transformations of the Classical Past, Princeton University Press, pp. 92–93, ISBN 978-0-691-18184-4, where you can read about the late 10th century CE Persian astronomer Al-Sufi and in particular, "Al-Sufi's book was translated into Latin and other European languages. Al-Sufi himself planned the figures, two for each constellation: one shows how they appear to an observer looking up toward the heavens; the other how they appear to the observer looking down upon a celestial globe." (pages 92–93). As for the images, I think the
Added image and footnote as per discussion. Having some trouble cropping image. Added the reversed one as that was the norm in celestial cartography. Cas Liber (talk · contribs) 11:33, 28 April 2020 (UTC)

Coord note

I'm going to sound like @SandyGeorgia: here, but can someone take pity on an old lady's eyes and ... not use so much color markup? It's very jarring and makes the FAC much harder to read. --Ealdgyth (talk) 23:21, 25 April 2020 (UTC)

So now you see what it's like to have old eyes and have to read through multi-colored text :) SandyGeorgia (Talk) 23:37, 25 April 2020 (UTC)
I've removed my orange. I realized after that my signature, rendered in some shade of goldenrod is warning enough that it is me, not someone else. Thanks for awakening that realization. Fowler&fowler«Talk» 23:55, 25 April 2020 (UTC)
Thanks, that helped a lot. --Ealdgyth (talk) 23:57, 25 April 2020 (UTC)

British or American

We need to choose a spelling convention. Attic Salt (talk) 14:41, 26 April 2020 (UTC)

I see only three spelling issues differences:
  • The topic "Rigel" does not have any country- or region-specific context, or right of first refusal in English. It was first known in Sumerian astronomy, then Babylonian, then ancient Egyptian, then after a long time in Greek, then Hellenistic, then ancient Indian, then Roman, then Byzantine, then Arabic, ... Then European Latin, and none were English speaking.
  • The pre-existing spelling within the article—an aspect of the vagaries of who amongst speakers of the world's regional varieties of English began to edit it first—has no heft in a topic as universal as "Rigel."
  • The spelling convention should, therefore, be decided on the basis of the spelling convention of the topic's semantic network. That is predominantly American English, as the above examples demonstrate—in this encyclopedia, that is. Fowler&fowler«Talk» 17:43, 26 April 2020 (UTC)
Probably many of the Britishisms came from me. My background means I often can't tell remember which way is which. If the article is largely US spelling and there is no compelling reason to change that, the rest can be converted. Lithopsian (talk) 19:10, 26 April 2020 (UTC)
@Lithopsian: I made it too complicated. The article is not largely any spelling. It uses only three instances of British spelling which I have listed in the first sentence. The rest of the article is written in spelling common to all Englishes. However, my reasoning for adopting AmE is simply that many of the links or related concepts are in AmE spelling. So, unless you want to watch the drive-bys—that will invariably keep sprouting up, changing "centre" to "center"—with the eyes of a hawk, you might as well change to AmE spelling. Fowler&fowler«Talk» 19:52, 26 April 2020 (UTC)
Being Australian I write in a hybrid of both anyway. Happy to streamline article to American if that means less work Article duly Americanized now! Cas Liber (talk · contribs) 20:01, 26 April 2020 (UTC)
:) I belatedly discovered MOS:RETAIN, which says, "use the variety (of English) found in the first post-stub revision that introduced an identifiable variety." With a view to ascertaining said variety, I landed on this version of 2015 edited by you. Well, that as far as I can tell had, "color," "center," and "modelling." So, the identifiable variety is "after every two American spellings, add one British." Fowler&fowler«Talk» 03:44, 27 April 2020 (UTC)
Ah well, we landed on the side of the majority and went with US. I was unwittingly prescient then...hehehe Cas Liber (talk · contribs) 11:16, 27 April 2020 (UTC)

Nomenclature

The section on nomenclature includes the following sentences: "However, Bayer did not strictly order the stars by brightness; rather he grouped them by magnitude class and then ordered the stars within each class according to a different scheme. Rigel and Betelgeuse were both considered to be of the first magnitude class, and in Orion the stars of each class are thought to have been ordered north to south."

The first sentence alludes to a "different scheme", though this is not explained. The second sentence mentions ordering "north to south" and says that this is "in Orion". Can we drop the allusion to "another scheme" and simply say that ordering was north-south or was this really just done for some constellations (like Orion)? Some consistency and succinctness might be possible, here, but I'm not sure. Attic Salt (talk) 14:00, 27 April 2020 (UTC)

Good point. Removed segment which doesn't really add anything specific Cas Liber (talk · contribs) 14:09, 27 April 2020 (UTC)