Talk:List of largest stars

Video Links

Removed second video link, as the video it links to is a ripoff of the original with a weak attempt at comedy at the end. Methylene 06:38, 5 January 2007 (UTC)

Excellent movie link.C1k3 07:55, 9 February 2007 (UTC)

References?

Feb. 23, 2007: There is NO references to be found in SIMBAD or STScI star catalogs for the two stars: Y1 (one) Aurigae J Cassiopeiae.

If valid source material can be given, with RA and DEC - it would be most helpful. Otherwise I am thinking these are typos and we need to figure out exactly what stars these are SUPPOSE to be.

JjB-54

I'm agree with you. No ref mentions J Cassiopeiae (Maybe it has exploded into a supernova) but, I think Y1 Aurigae means Y Aurigae (Spectral type=F5-F9) (It is one of largest F-type supergiants with a radius around 511 solar radii (711,005,400 km)). It was just a typo. Gotorn 999999 (talk) 09:43, 1 July 2017 (UTC)

Contradiction Antares/Betelgeuse

Betelgeuse [...] if it were placed at the center of our solar system, its outer surface would possibly extend to the orbit of Jupiter.

Antares [...] with a diameter of approximately 1.33 × 10^9 km. I.e., if in place of our sun, it would slightly more than encompass the average orbit of Mars.

... and yet Antares is larger than Betelgeuse !

Somebody please check & correct.

Memo

Betelgeuse's size is variable (between 500-800 Sol's), so the 650 size is an average. I think the Jupiter statement just refers to the max size of 800, so Antares is correctly listed above Betelgeuse, as this is fixed at 700. The Solar radius is 0.0046 AU, giving Antares a diameter of 3.25 AU and Betelgeuse 3 AU (r=650) or 3.72 (r=800).

*The distance to Mars varries from 1.4 AU (min.) to 1.7 AU (max.)

*The distance to Ceres varries from 2.5 AU (min.) to 3 AU (max.)

*The distance to Jupiter varries from 4.95 AU (min.) to 5.46 AU (max.)

So actually, neither the Mars- or the Jupiter statement is correct, both stars are between these two. Patrick1982 14:33, 14 March 2007 (UTC)

Relations between Solar radius and Orbital radius of planets

Solar radius(R) = 6.96 × 10⁵ km.

Astronomical unit(AU) = 1.49597870691 × 10⁸km = 214.9 Solar radius.

List of orbital radius of planets

Planet	(AU)	solar radius = 1.0	example stars
Mercury	0.31 - 0.47	66 - 100	Rigel(70)
Venus	0.73 - 0.73	156 - 158
Earth	0.98 - 1.02	211 - 219	Deneb(220)
Mars	1.38 - 1.67	297 - 358
			Alpha Herculis(460) Betelgeuse(650) Antares(700)
Jupiter	4.95 - 5.46	1064 - 1173
			VV Cephei (1600-1900)
Saturn	9.02 - 10.05	1939 - 2161	VY Canis Majoris (1800-2100)
Uranus	18.29 - 20.10	3930 - 4320
Neptune	29.81 - 30.33	6408 - 6519

Kometsuga 11:39, 15 March 2007 (UTC)

Radius versus Diameter

Looking over the Solar diameter, I see the measurement is the same as the solar radii for Antares. Diameter is not radius. —The preceding unsigned comment was added by 71.241.214.116 (talk) 08:45, 3 April 2007 (UTC).

Quite; I am wondering in the table how the Sun's diameter can be specified as "1 Solar Radius" - Pythagoras would have a fit; something is clearly wrong. —Preceding unsigned comment added by 192.18.1.36 (talk) 10:27, 24 October 2008 (UTC)

Distance from Earth

I think it might also be useful to add the the chart a listing of the distance from Earth in light-years for each star. 147.145.40.44 22:48, 30 April 2007 (UTC)

Also spectral class should be added.CFLeon (talk) 20:38, 30 October 2008 (UTC)

Distance from earth is often not known and measured in parallax instead of light years. Often from one side of the sun's orbit to the other. Confirming being within the Milky Way would be helpful. — Preceding unsigned comment added by 2602:304:AF40:3149:C4F6:8738:5F89:D0F (talk) 14:16, 23 January 2015 (UTC)

All the stars listed are in either the Milky Way or the LMC. Tarl.Neustaedter (talk) 19:04, 23 January 2015 (UTC)

A1 in NGC 3603

This is an ultra massive star, likely the largest on this list, but I did not track down its diameter. [1] —Preceding unsigned comment added by 68.145.187.67 (talk) 17:06, 22 April 2008 (UTC)

See List of most massive stars The Yeti (talk) 02:50, 3 July 2009 (UTC)

Move

Why is this page protected from being renamed ('move') ?

And would not it be better called List of largest stars by diameter ? As just 'largest' is ambiguous (eg mass ?) Further, you can drop 'known', as by definition, we can only list known stars ... we can hardly list the unknown ones ! The Yeti (talk) 02:50, 3 July 2009 (UTC)

I also feel there is a little ambiguity in the article itself. I recently heard news that a new record for the largest star was discovered. I tried looking up largest stars on Wikipedia and came to this article, but it doesn't really mention the important mass/diameter distinction. I found the new record turned out to be for the most massive star, R136 and mentioned in the List of most massive stars. I wish/think there could be maybe a sentence or two comparing the importance and especially how mass and diameter affect each other, or if that's out of place, then maybe a link to which article might explain it. ZeniffMartineau (talk) 14:52, 22 August 2010 (UTC)

Agreed on the ambiguity. I'd support List of largest stars by diameter as the new title. A move can be requested here. mgiganteus1 (talk) 21:27, 22 August 2010 (UTC)

The difference is the largest versus the heaviest. Perhaps this could be called List of most voluminious stars though. 76.66.196.13 (talk) 12:15, 26 October 2010 (UTC)

"Large" generally refers to size, not mass (a black hole can be very massive without being all that large, ferexample). To the extent that there is an opportunity for confusion, I think the link to the List of most massive stars right at the top solves it pretty well. On the other hand, I agree that "known" is redundant. As for "voluminous": it's a charming word, but my instinct says no. It's not something that leaps to mind, and I don't think it's a standard term of art. If we did use "voluminous", we'd need redirects for more commonly searched terms. Plus (as 76.66.196.13's own comment shows), it's not the easiest word to spell. Xtifr _tälk 20:11, 11 March 2011 (UTC)

historical list

Perhaps a list of stars historically considered to be the largest should be added?

For instance, apparently the dark companion of Epsilon Aurigae was hailed as the largest (diameter) known star, incorrectly attributed to being a star, in 1970... (it's not considered a star anymore, rather more likely a dust disc around a binary pair)

• Ottawa Citizen, Ask Andy: The Biggest Star, American Family Features, Fri 27 Nov 1970, p.44

65.94.47.63 (talk) 11:24, 13 June 2011 (UTC)

Hype

I'm in the process of going through the published data for the stars in this list and it appears that much of the table is effectively big number hype. People seem to have gone through anything on the web. pulled out the biggest number they could find no matter how old or how poorly supported, and thrown it in the list. Some of the information is simply wrong, for example mu Cephei apparently here because of a typo, and now the data has been copied all over the web. I'm gradually editing the table, adding notes to many of the entries and changing data that is clearly wrong or has been supplanted by reliable recent research. Obviously most of the results are subject to a considerable amount of uncertainty to the extent that the order of the table itself is somewhat arbitrary. Lithopsian (talk) 12:24, 20 May 2012 (UTC)

VY CMa

The quoted reference for this star (Choi et al) gives a preferred temperature of 3,650K and a luminosity of 300,000. That equates to a radius of 1,370. The paper gives a likely luminosity range of 250,000-350,000 which equates to a size range of 1,200-1,500. It additionally refers to earlier works quoting a possible temperature as low as 3,000K, although pointing out the reasons why this is unlikely. Using the lower temperature gives the possibility of a radius as high as 2,200. Being so frequently quoted as the largest star, I understand that people have an emotional attachment to it, but if you want to change the numbers please include a reference source to support them, preferably one that hasn't been superceded. The 1,800-2,100 range is from an older paper that hasn't been in the list of references for nearly two years. — Preceding unsigned comment added by Lithopsian (talk • contribs) 22:32, 25 May 2012 (UTC)

Stand by for fireworks. I just moved VY CMa to 7th in the list, based on the currently quoted diameter (1420x) from the detail page. The very large estimated ranges previously shown (1200-2200) overlapped with any number of stars and the position could legitimately have been anywhere in the top ten or more stars, so the current position is not fundamentally any different. Lithopsian (talk) 22:53, 16 July 2012 (UTC)

Well that wasn't so bad. Interesting how quickly people have started reporting NML Cygni as the largest star, although to be honest nothing has really changed and there are still half a dozen well known red hypergiants essentially the same size within the margins of error. I just added one completely new to the list, W26 in Westerlund 1. It has a very large reported size, even at the smaller end of expectations, but please don't start jumping up and down about it being the largest. This star simply hasn't been studied in detail to determine its diameter, the temperature is poorly defined and probably variable, the distance is still subject to debate, and the luminosity estimates are uncertain because it has some very non-standard properties. Definitely an extreme red star though and needs to be on the list despite the uncertainties. Lithopsian (talk) 14:21, 29 October 2012 (UTC)

Cull

There is a lengthy list of stars in this article that can in no way be considered the largest, not close, not ever, not by any margin of error. They fall below the line marked "well-known stars are listed for the purpose of comparison". I propose that this line be moved to perhaps 1,000 since there are certainly stars of that size not listed, and that stars which are not household names or exceptional in some other way (for example the most massive or a prototype of some class) should be removed. This would mean perhaps three quarters of the list below that level would be deleted. For example, what is Eta piscium doing in the list, or 11 Ursae minoris or Xi Aquilae? Lithopsian (talk) 14:15, 29 October 2012 (UTC)

I have ruthlessly pruned the "for comparison" section of this list. It made no sense for it to be several times the length of the actual largest known stars section. I feel that stars in the comparison section should be 1) Well known. If it doesn't have a common name or a Bayer Designation that's not a good start. 2) Noteworthy for some reason - and if it's the same reason for more than one or two of them then the redundant entries can be removed. 3) The comparison list shouldn't be more than half the length of the main. M0ffx (talk) 16:22, 1 December 2012 (UTC)

New largest star?

Westerlund 1-26 has been moved to the top of the list. The data listed for this star is even more uncertain than the previous entry NML Cygni, little more than a guess if you read the journals in detail. I'd appreciate someone checking into the papers to see if the listed sizes can be supported. There are three references given and one of them clearly gives data for temperature and luminosity that equate to the upper bound, although it doesn't actually specify a diameter and the uncertainties around the (probably variable) temperature and luminosity are high. For all my searching through the other two references I can't see where the lower bound comes from. I suspect I was the person that originally typed in those two numbers. Given that I (or someone else) didn't also put W1-26 at the top of the table, I wonder if the lower bound was a typo of a smaller number. Lithopsian (talk) 13:38, 14 September 2013 (UTC)

It really matters for every number you type, though, especially if there are a dozen or more stars battling to the first place. As it was said, these stars undergo strong mass loss emitting clouds of masses that make their size measurement very doubtful to impossible. Of course, we must state the exact rankings of the following stars. Pretty much sure though that some stars have upper diameter estimates of surprisingly large sizes, like KY Cygni. It can be as large as VY Canis Majoris at 1,420 × Sun, or it could be the "Mother of All Stars" at an outstaggering 2,850 × Sun. Assuming its highest estimate is correct can blow out all stars in the list, even Westerlund 1-26's highest estimate is correct. But funny it's 7th now. That's how we need to apply in here, critical thinking. We pin down all possibilities. We can't just type a star in here and apply its diameter without looking at possible chances. If we only look at the star's higher estimates and put it here, it can be pretty sure though that we access wrong information, especially if we don't look at reliable journals. But I'm really respected to you because you type your words with sources. ==Johndric Valdez (talk) 11:18, 24 September 2013 (UTC)==

RSGs in four Scutum clusters

I've found out info about four star clusters in the constellation Scutum, namely RSGC1, Stephenson 2, RSGC3, and Alicante 8 contains lots of red supergiants, probably a few hundreds or more. Should we include it in this article, or let someone measure the stars' sizes? Johndric Valdez (talk) 07:09, 9 February 2014 (UTC)

Cutoff Point

I don't understand why the list still goes down to R Lep at 500 R. The above aforementioned itself states "44 red supergiants are larger than 700 R". Obviously those 44 are not in the list, making the table inaccurate. Plus, those below the 700 R must be removed; it's nonsense to put them in the table.

I suggest to move the cutoff point well to 700 R or larger. Comments please. SkyFlubbler (talk) 09:48, 17 December 2014 (UTC)

Values for sizes, in particular VV Cep

A general comment on the specific sizes listed - in many ways, specific ranking is an exercise in frustration, defining how many angels dance on the head of a pin. The exact size of any given giant star has huge error margins, due to various factors listed at the top of the article including asymmetry, precise boundary of atmosphere, imprecise knowledge of distance to star, and imprecise optics.

Whatever values are listed here, please ensure they are precisely the values you find in the reference. Averaging between multiple sources introduces noise, making it more difficult to determine where the value came from. In the specific case of VV Cep, which has seen recent activity, the two cited values come from two different measurements - 1,900, published 35 years ago, and 1,050 published in 2008. The original measurement was a ground-based measurement, the more recent one derives from Hubble observations. That usually suggests a more precise measurement. Either way, the only values we should list are the ones specified in the articles - either one article is to be believed or the other. Coming up with a third value obfuscates the original data.

Remember, what Wikipedia is supposed to be is a summary with pointers to where the information came from, not a primary source itself. Any alteration of data from the original citations increases the difficulty of tracking down what actually is known. Regards, Tarl.Neustaedter (talk) 05:34, 24 December 2014 (UTC)

This issue is already on the WT:AST, at Wikipedia talk:WikiProject Astronomy#List Break-up. That is one of my regards. This Asyulus is already making a huge misconceptualization. One must need to fix this guy.

Pinging at Tarlneustaedter- I know you're the real expert here. Can you fix those suspicious values? Plus, give more details on the discussion. SkyFlubbler (talk with me :-D) 10:31, 27 December 2014 (UTC)

Sorry SkyFlubbler, I'm not a particular expert in the subject matter. I'm a firmware engineer, my last formal astronomy coursework was in the 1970s. While I do follow the literature, allowing me to spot cases that are blatantly off-kilter, my role on Wikipedia is primarily sanity-checking references against what I see in the articles. I don't have access to the kind of research library which would allow me to carry out a comprehensive update as you suggest. Regards, Tarl.Neustaedter (talk) 23:28, 27 December 2014 (UTC)

Random numbers off the top of your head

There have been another series of edits in the last couple of days (you know who you are) changing the values in the table to numbers either remembered from some long-obsolete blog or just plain made up. This is not acceptable, never has been, and will always get reverted (undo with a comment if I'm feeling in a good mood). The values in the table must be verifiable. Most simply this means using the same number as the individual star article. In some cases, a different external source might be cited, but usually the individual star article should be changed to match. Just changing a number because you want one star to be at the top of the list. or because you don't like a particular star or have never heard of it, or because one star was the most famous when you were a small boy, are not valid reasons to edit this article. Doing so repeatedly is a good way to get yourself banned, or the article locked. Lithopsian (talk) 14:13, 26 February 2015 (UTC)

Proposed merge with List of largest stars 2

This appears to be the same information, with one new star added to the top of the list. I could be wrong, I didn't do a line-by-line comparison, but nevertheless they cover exactly the same topic. Gronk Oz (talk) 10:18, 23 September 2015 (UTC)

You're not wrong. It is clearly simple vandalism. Might I suggest a speedy delete? Lithopsian (talk) 10:25, 23 September 2015 (UTC)

I curated it myself. It is now nominated for speedy deletion. Lithopsian (talk) 11:33, 23 September 2015 (UTC)

Thanks for that. Sometimes I give a bit too much benefit of the doubt... --Gronk Oz (talk) 11:36, 23 September 2015 (UTC)

Please move List of largest known stars to List of largest stars, per concensus

"Known" should be removed from the article title per this WP:AST discussion. Please discuss there, if needed. Thanks!   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  15:35, 5 January 2016 (UTC)

The page was protected against moves. I have moved it for you. Graeme Bartlett (talk) 23:49, 5 January 2016 (UTC)

Semi-protected edit request on 7 January 2016

89.156.137.161 (talk) 00:17, 7 January 2016 (UTC)

• Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format. We aren't going to play find the differences. Copying the entire article is not an edit request. Please be specific with the changes you want to make. --Majora (talk) 00:55, 7 January 2016 (UTC)

EV Carinae

If Lithopsian's numbers are correct, this is the "monster of all monsters". However, I hope someone will get a reference for this. It just appeared like a bubble on top of UY Scuti.

The reference 2 has no data about the radius. So, I am calling those who watch this article and other users to clarify and find data concerning this star (esp. Lithopsian, you put that star on the list). I will tell this to the Wikiproject Astronomy talk. SkyFlubbler ^(talk) 06:33, 16 January 2016 (UTC)

Okay, so EV Carinae. A star that is according to SIMBAD, a red supergiant. That is virtually all the data about this star. Any thoughts? SkyFlubbler ^(talk) 06:38, 16 January 2016 (UTC)

I went ahead and undid the edit for now. As far as I could tell from looking over its tables, the referenced paper didn't even mention EV Carinae. I think the addition of a new largest star absent any new discoveries or measurements requires some discussion in any case. @Lithopsian:, can you explain your reason for adding the star? A2soup (talk) 07:44, 16 January 2016 (UTC)

SkyFubbler pointed out to me that EV Carinae is, in fact, in the ref on p. 280, NR 231. Still, I don't see a clear indication of the radius and think we definitely need discussion before adding it. A2soup (talk) 18:30, 16 January 2016 (UTC)

By the way, I created a draft, for now. It is not yet a formal article: User:SkyFlubbler/EV Carinae. SkyFlubbler ^(talk) 06:39, 16 January 2016 (UTC)

Mind moving it to DRAFT-space? Then we could add tags for draft articles to it -- 70.51.44.60 (talk) 10:57, 16 January 2016 (UTC)

There seems to be an article about this star here, but the server appears to be down, so I can't retrieve it. Tarl.Neustaedter (talk) 13:52, 16 January 2016 (UTC)

I agree that every editor that adds to this list should be as specific as possible on the reference, at least with a required |page=, |at=, and/or |quote= parameter, so that it may be easily verified by readers or editors. This "new" star's reference (from a 1988 source) is highly lacking and I agree with its removal as-is.   ~ Tom.Reding (talk ⋅dgaf)  15:41, 16 January 2016 (UTC)

I've added some references to SkyFlubbler's draft. I was somewhat surprised that there was no Wiki-article for this star. It is clearly one of the most luminous known red supergiants, and hence one of the largest, as well as being a large amplitude and reasonably bright variable star. Detailed research specific to this particular star is somewhat lacking, and the basic physical data are highly uncertain. Probably no more uncertain than the other stars near the top of the list, but very obvious from the conflicting published values. You can see some basic data here. This refers back to the reference I originally included in the list, but it was quite difficult to deciper. The newer paper actually derives an even higher luminosity. I've now found this paper which derives values more in line with expectations for this type of star. An article would be good, then it becomes easy to link into this list. Lithopsian (talk) 20:37, 16 January 2016 (UTC)

It looks like those papers give luminosity, temperature, mass loss, and other values, but I don't see radius in either of them. Is the calculation to derive radius from this data so straightforward that it doesn't run afoul of WP:OR? Because I would imagine that if it was that straightforward, it would not be hard to find a reference giving the radius. Or is there a reason that the papers refrain from deriving a radius estimate? A2soup (talk) 20:50, 16 January 2016 (UTC)

The papers don't quote radii directly, which is unfortunate for our purposes. It is a trivial calculation to derive a radius from luminosity and temperature, although there are at least half a dozen ways to define the radius of a star. In most cases the various values are all but identical, but for a red supergiant they can be significantly different. Different papers derive different types of stellar radius depending on the type of observations or models involved, and the list here doesn't really make any attempt to distinguish them. In some cases the values quoted in the list are explicitly not comparable, for example at optical depth 1 vs 2/3. NML Cygni was a previous example that got catapulted to the top of the list based on papers that didn't explicitly published a value for the radius, only for luminosity and temperature and those with a huge possible range. UY Scuti actually has a recent paper that explicitly derives the radius, convenient for WP:VNT, but ultimately just another single source with a margin of error larger than the difference between it and a dozen other stars. Lithopsian (talk) 21:03, 16 January 2016 (UTC)

I don't think Lithopsian's calculations fall inside WP:OR. You need data in order to derive it. Like when 2+3 you get 5 even though not stated by the reference. EV Car must be certainly included, because the data about it states that it was a large star, though with an unknown size. SkyFlubbler ^(talk) 06:05, 17 January 2016 (UTC)

Hm, thanks for the info, that's very helpful. It seems to me that in the special case of red supergiants, the determination of the star's radius is a non-trivial affair, not because the calculations are questionable, but because the most appropriate model is not well-established and may vary by star. Based on this, I think it is reasonable to suggest that:

1. in the interest of WP:OR and WP:VNT, we only give the radii of red supergiants in cases where an explicit derivation has passed peer review (for the red supergiants that are doubtless very large but do not have published radii, we could add a note like: "Red supergiants x, y, and z are likely among the largest stars, but their radii have not yet been adequately determined.),
2. give the type of stellar radius in the "Notes" column for each red supergiant, and
3. where there are multiple equally-valid published values for radius (red supergiant or not), we list them all in bold (with ±error?) with a ref directly on each number.

What do people think of these suggestions? A2soup (talk) 06:27, 17 January 2016 (UTC)

Okay, the draft of mine has been accepted, at EV Carinae. SkyFlubbler ^(talk) 07:19, 17 January 2016 (UTC)

Should I include it? Because no consensus has been made so far. SkyFlubbler ^(talk) 07:20, 17 January 2016 (UTC)

Three straight days had passed without any response. To clarify my point, I've jot down a few details:

If we observe the available data we have for EV Car, based on the paper given by Lithopsian:

Spectral type: M4Ia, so a red supergiant Temperature: 2,930 K, consistent with spectral type Luminosity ratio L/L_Sun: 5.74, that is, 550,000 times brighter than the Sun

These values are high compared to other supergiants. From what I've heard, the size of a star is proportional to its luminosity and inversely to its temperature. The Rossland radius of these types of stars are confusing, either 1 or 2/3. But the reference is clearly stating EV Car is a very luminous, cool supergiant that should be of unprecedented size. But the number of 2,880 is too high for me, since the Hayashi limit states 1500-2000 solar radii based on the Milky Way metallicity.

EV Car's size must be defined as soon as possible, since tracing the size of this star is very tricky. SkyFlubbler ^(talk) 14:00, 19 January 2016 (UTC)

I agree that it would be nice to define EV Carinae's size ASAP (as well as that of NML Cygni and other red supergiants without published radii), but we just can't move faster than the literature on this. We have to wait until a radius is published in a reliable source before the star can be added to the list proper or have a radius listed. As frustrating as it may be, Wikipedia is a recorder, not a generator, of knowledge, and scientific knowledge is incomplete. The radii of red supergiants is a tricky question, especially when we are dealing with highly unusual super-large stars. Since these stars are poorly understood, their radius is not at all straightforward to calculate as with main-sequence stars (Lithopsian, do you agree?), so I don't think it's responsible for us to independently derive radii and rank the stars here. It's frustrating since we know they are very, very large, but I think verifiability, not truth is the order of the day. I agree that more input would be very helpful *cough* anyone watching this page *cough* A2soup (talk) 14:19, 19 January 2016 (UTC)

Two things worry me here: 1) The multiple different definitions of radius e.g. corresponding to a particular optical depth at a particular wavelength. That's problematic for all entries on this list, which are not strictly comparable, but I suppose EV Carinae is no different to the others in that sense. 2) The oversimplification of calculating the radius from the temperature and luminosity. This is particularly problematic for cool (red) stars, which are far from being black bodies, so the Steffan-Boltzmann law is at best an approximation. In addition, the luminosity often has a huge error bar (usually due to distance uncertainty), which is not always obviously stated in the source.

I think the best solution is to adopt A2soup's suggestion to say something like 'the radius is expected to be very large, based on the temperature and luminosity, but has not yet been accurately determined' in the individual articles and omit such stars from this list until a peer-reviewed value is published. Modest Genius ^talk 13:26, 20 January 2016 (UTC)

You've got this seriously wrong. This is not picking some random temperature and assuming that it can be related to blackbody output. The definition of effective temperature is the temperature at which a blackbody would emit as much radiation as the star. It is precisely the temperature which can be multiplied by the radius (squared, to the fourth power, etc.) to get the bolometric luminosity. There are no assumptions and no approximations. It may differ from the "actual" temperature, to the extent that such a thing can be defined or measured, but almost all published literature quotes the effective temperature, and even models of stellar atmospheres work with it because it is more meaningful than other definitions of temperature. It is true that this "temperature radius" may not be exactly equal to a different definition of radius based on density or opacity, but it is no less valid than those definitions, in fact it is far less arbitrary. Definitions such as an the radius at opacity 2/3 are chosen to match as closely as possible in the case of stars with tenuous atmospheres. You should read Levesque 2005 if you have any doubts at all about this (see page 982 in particular), it isn't just me making it up. And you (ie. Wikipedia) can quote her on that :) Lithopsian (talk) 14:13, 20 January 2016 (UTC)

I am well aware of the definition of effective temperature, although I haven't read that particular source. Using T_eff to derive a radius is nevertheless an approximation, to one particular definition of radius. That approximation becomes more problematic at lower temperatures because the concept of radius becomes more fuzzy and more heavily wavelength dependent. The models used to derive T_eff are also less accurate and less well constrained for non-dwarf stars, particularly various forms of red giant and red supergiant (which happen to top this list), whose evolutionary status is not clearly and unambiguously understood. Different models and assumptions of evolutionary stage will give different values of T_eff and thus different radii, in a non-linear fashion. I didn't say the method was wrong, just that it is an oversimplification. I agree that these issues do not apply solely to EV Car, but I do think we should be clear on which values are taken from the peer-reviewed literature, and which have been calculated by Wikipedia editors. Modest Genius ^talk 11:38, 21 January 2016 (UTC)

I agree with this and suggest that we use an asterisk in the table with a note that reads something like "Radius not published; calculated from published [parameter x] and [parameter y]". A2soup (talk) 17:51, 21 January 2016 (UTC)

That would solve my concern about maintainability. Although I'd suggest a footnote rather than an asterisk, so the particular parameters published can be cited. Tarl.Neustaedter (talk) 22:27, 21 January 2016 (UTC)

The issue of (in-)accuracy is entirely relevant, but there is no problem that applies to EV Car more than to any other star on the list. How do you think the radius of UY Sct was calculated? From the luminosity and temperature, of course. The luminosity was actually calculated from SED fitting, which is now becoming very reliable, and an assumption of the distance, which is far from reliable. In the case of UY Sct, the luminosity is particularly unreliable because the SED fitting was based on a variety of photometry with different instruments at different times for a star that is known to be variable to a significant degree. It is almost certainly the case that the only reason UY Sct, or any other star that happens to be at the top of this list on a particular day, is there entirely because the errors involved in its calculation randomly happened to all line up the same way. There are sound reasons to think that VY CMa, for example, is a more extreme object and hence likely a bigger object. I'd put money on the next paper to study UY Sct coming up with a significantly different radius, 99% likely to be smaller. Try and get that across in the article by all means, but don't use it as an excuse to cherry-pick. Lithopsian (talk) 14:19, 20 January 2016 (UTC)

The problem is that to avoid WP:OR, we need to find a publication that actually states a radius. We're a tertiary source - a librarian with limited knowledge of the subject has to be capable of maintaining the article. If someone changes the size without explanation, someone without your expertise has to be able to challenge the change. That only works if the referenced citation actually states what is being listed in the article. A footnote describing what you say above (including citations as to the meaning of the various pieces and formulae) might go a ways towards making the entry maintainable, but a standalone entry with a radius not published elsewhere is a maintenance problem. Tarl.Neustaedter (talk) 16:29, 20 January 2016 (UTC)

After reading Modest Genius and Lithopsian's remarks, and adding to Tarl.Neustaedter's, I would be ok with identifying the current column on the page as "published radius", and have an additional column "simplified calculation" (or similar), with a clear and detailed note describing the steps of that calculation in enough detail for someone to reproduce it (references for each value used would be required; hopefully they'd all be in the same paper), and applying that to each star. By default, I think the list should be sorted by published radius, but the reader can then choose.   ~ Tom.Reding (talk ⋅dgaf)  16:52, 20 January 2016 (UTC)

For reliability purposes, you could add a section listing the largest stars that have directly measured angular sizes. For example, stars from the CHARM2 catalogue. Praemonitus (talk) 00:53, 21 January 2016 (UTC)

Now EV Carinae is 1,168 Rsuns R_☉, it has a temperature approximately 3,574 K, a luminosity approximately 200,000 R_☉ ! Space Infinite (talk) 18:51, 16 July 2016 (UTC) !

Lead image

The lead image with NML Cygni and UY Scuti is the same as the POTD lead image without them, just with the last 3 stars re-named and re-textured. Obviously, since this is a size comparison, this sort of "update" is not an update at all-- it doesn't make the image more current, just inaccurate. What tipped me off that something was wrong was that the "update" was done by Jcpag2012 (incorrectly sourced as "own worK"), an editor who caused a lot of trouble across astronomy-related articles and was eventually indef blocked for WP:COMPETENCE. Because of this, I am changing it back to the POTD. A2soup (talk) 18:50, 16 January 2016 (UTC)

Sirius A

67.55.19.24 (talk) 03:07, 4 February 2016 (UTC)

Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format. EvergreenFir (talk) Please {{re}} 03:24, 4 February 2016 (UTC)

NML Cygni

If NML Cygni's estimate would be 1642-2775, It might as well be placed above UY Scuti since VV Cephei A surpassed VY Canis Majoris by also using 1050-1900 instead of only one estimate. VV Cephei A was higher than VY CMa because 1050-1900 is 1475 so NML Cygni would be larger than UY Scuti because 1642-2775 is 2208.5 (3,075,742,614 Km) and UY Scuti is 1708 (2,378,704,272 Km). (posted by V255 Canis Majoris)

1050 - 1900 is *not* 1475. These are independent calculations by different authors. One of them is wrong, and the other is ... well, less wrong. The 1090 figure is actually ancient and should probably be dropped, but people do so like their big numbers. Lithopsian (talk) 20:14, 28 April 2016 (UTC)

But NML Cygni is smaller than Mu Cephei (1.753 billion km) and UY Scuti (2.38 billion - 3.863 billion km) with 1,183 solar radii now (1.646 billion km). (posted by 77.192.212.179)

@V255 Canis Majoris. Even 1,642 - 2,775 R_☉ is *not* 2,208.5 R_☉. You can't take an average of two unrelated numbers ! 1,642 and 2,775 are two independent calculations without error ranges. We have no basis for averaging them or inventing a statistical error range, and even if we did have data for weighting them and performing statistical manipulation, that isn't Wikipedia's job.

Don't you think that NML cygni's radius should be listed as 2,212.5 ± 562.5 solar radii? Cause UY Scuti's is listed as 1,708 ± 192 R_☉ and not 1,516-1,900 R_☉. Absolutely not. Nobody has ever published a (meaninglessly precise) number 2,212.5.

And even WORSE from the NML Cygni's article, is that there is no reference, nor is it cited in NML Cyg's starbox. Anyone causally reading the starbox has no idea what "1,642 (– 2,775)(2,208.5?) R_☉" actually means ! THE INFINITE SPACE (^Discussion | _Contribs | ^dgaf) 10:41, 20 August 2016 (UTC) !

VX Sagittarii

If VX Sgr estimate would be 1350-1940, It might as well be placed above WOH G64 because 1350-1940 is 1645 (2,290,965,180 Km) and WOH G64 is 1540 (2,144,733,360 Km). — Preceding unsigned comment added by 77.192.212.179 (talk) 10:18, 17 June 2016 (UTC)

Another tricky one. The Lockwood and Wing reference is old and there are certainly better models and calibrations available today, but I can't find anybody who has taken the trouble to observe over a full range of variations (7.5 magnitudes in the visual!) and calculation the variation in the physical parameters.

However, it is not valid to just take an average of the maximum and minimum radii. That would be original research. Find a number that is quoted in a reliable reference, or at the very least can be unambiguously and trivially calculated (eg. by changing the units).

In this case, an average may not be the appropriate "single number" to use even if you could find a source for it, since these types of stars are often observed near maximum and then physical data calculated for that one point in time. For example, see Mauron & Josselin, the photometry for VX Sgr is very close to maximum, giving a relatively luminous, hot, and small result. The same is true for UY Scuti, calculated to be 1,708 solar radii from photometry near maximum light, but almost certainly different at other times. And the radius corresponding to the higher temperature would be 1,350 R_☉, and the lower would be 1,940 R_☉. THE INFINITE SPACE (^Discussion | _Contribs | ^dgaf) 20:06, 19 June 2016 (UTC) !

1,350 - 1,940 is not 1,645. You made that number up. No matter what your basis was, if it isn't supported by a reliable reference then it can't go in Wikipedia. This list lacks any defined criteria for working with actual variable radii, or even with statistical error ranges to be honest, but that isn't an excuse for defining your own radius. Lithopsian (talk) 20:16, 19 June 2016 (UTC)

And in general, when a range, use the small end of the range to sort, not the high end or some middle range. THE INFINITE SPACE (^Discussion | _Contribs | ^dgaf) 20:44, 19 June 2016 (UTC) !

So, VX Sagittarii is smaller than WOH G64 (2,144,733,360 — 2,409,343,320 km) and AH Scorpii (1,965,077,124 km) with 1,350 R_☉ (1,880,123,400 km) ! And It is the 9th largest star ! THE INFINITE SPACE (^Discussion | _Contribs | ^dgaf) 18:51, 21 July 2016 (UTC) !

Intervals of size.

I suggest that if you see the stellar intervals of size, just get the median size of stars.Julliene mae (talk) 13:56, 6 August 2016 (UTC)

Not going to happen. We have no way of weighting the ranges given. Some of them are from different authors, obtained by different techniques. They are often "one or the other", not "somewhere between the two". The article should quote the sources and nothing more. Lithopsian (talk) 19:52, 6 August 2016 (UTC)

Timeline

This whole thing looks very difficult to justify. Some of the quoted sizes have no citations at all and don't match the linked article, some have citations but the quoted size doesn't appear to be in them, and there doesn't seem to be any way of deriving the date ranges from the given citations. Tagging for now. Maybe it can all be made verifiable, but it is a long way short at the moment. Lithopsian (talk) 19:55, 6 August 2016 (UTC)

More interestingly, even if we can verify that the stars were believed to be the sizes in question on the dates in question, how can we verify that they were the "largest (known) star" in the years in question? Tarl N. (discuss) 20:37, 6 August 2016 (UTC)

I'll mention one (of many) very obvious problems with establishing this timeline. NML Cygni is listed as having a radius of 1,650 R_☉ and being the largest star from 2012-2013. The NML Cygni article currently cites a size of 1,050 R_☉ from a 2010 paper. Clearly it wasn't the largest known star in 2012 or 2013. Possibly it was the largest star as reported in Wikipedia, but it hardly makes sense to be reporting that if we now know it was wrong. Lithopsian (talk) 19:50, 13 August 2016 (UTC)

It was WOH G64 the largest from 2012 ? — Preceding unsigned comment added by Red Planet X (Hercolubus) (talk • contribs) 20:38, 14 August 2016 (UTC)

Who knows? That's the whole point. It is almost impossible to know, almost pointless even asking, and certainly not sensible to put it in Wikipedia without a lot better supporting research. Lithopsian (talk) 20:43, 14 August 2016 (UTC)

Section probably should go. Largest star is wrong anyway. Better would be largest known, but as size may shrink as remeasured that sounds wrong too. Largest measured known stars... -Koppapa (talk) 11:42, 20 August 2016 (UTC)

I have removed the timeline section. This page is on my watchlist, but I rarely look at it, so I did not follow the development of the section. I can tell you, however, that as someone with a passing knowledge of astronomy, the section made very little sense to me. The "largest stars" seemed to get consistently smaller over time, the start date of 1970 made no sense, the comments were confusing and did not correlate with information in other columns, etc. I don't think such a timeline is a good idea in the first place, but even if we were to agree to have one, the one I just removed would not work at all. A2soup (talk) 01:11, 26 August 2016 (UTC)

Thanks. Tarl N. (discuss) 01:53, 26 August 2016 (UTC)

I question the neutrality of the article because it uses subjective words such as "notable" and "well-known".

Those two words are unnecessary. Wikipedia should not use those kinds of subjective terms. It is subject to introductory bias and is often used by insignificant POVers to deNPOVify articles whilst being hidden from experienced users' anti-bias radars. Unless you can cite a study contradicting what I just said. I find the essay WP:CIR confusing and I am also ridiculing experienced users' references to WP:CIR since it's just an essay and is not a policy or guideline, or maybe it's just one of those essays that are treated just like policy. It seems that some experienced editors want to focus more on making Wikipedia look better rather than make Wikipedia less instructional, more neutral or less about the writer and reader. --Turkeybutt (talk) 00:32, 6 September 2016 (UTC)

"Notable" does not appear in the article. "Well-known" is used precisely because these stars are well-known, so that we can list them here to begin with. The ones that we don't know, cannot be listed. This has nothing to do with neutrality. - DVdm (talk) 07:34, 6 September 2016 (UTC)

We know about over a million stars. So if we know a million stars, then we can list all of them on the list, but we shouldn't. That would be too much. Please define well-known. Many people don't know about these stars, so using the non-neutral 'well-known' would be unverifiable nonsense. Verifiability and neutral point of view are super important to me. I put neutrality and verification as my top two priorities on Wikipedia. --Turkeybutt (talk) 18:40, 6 September 2016 (UTC)

Note that you are topic banned—see wp:topic ban. Continuing this will get you blocked—see wp:block. See your talk page User talk:Turkeybutt JC#Notification. - DVdm (talk) 19:22, 6 September 2016 (UTC)

Given that if the list today was the exact info even from before without us knowing

Then wouldn't that make V354 Cephei the largest from its discovery until 2008 then surpassed by RW Cephei then WOH G64? If WOH G64 came first then it was the largest from that time until UY Scuti came. (Not Westerlund 1-26 or NML Cygni or VV Cephei A or VY Canis Majoris or Mu Cephei) Right? — Preceding unsigned comment added by V255 Canis Majoris (talk • contribs) 08:28, 24 September 2016 (UTC)

VY Canis Majoris vs. KY Cygni

What's the difference if I put VY Canis Majoris above KY Cygni since it was a title holder anyway? And if KY Cygni's 2850 is considerable then put a different radii for KY Cygni and do your best to confirm any radii other than 1420. If you can't do that, it stays in 1420 and VY Canis Majoris wins. Or does Wikipedia just wanted KY Cygni to be above VY Canis Majoris? Explain to me why KY Cygni keeps on going higher than VY when it is no difference and recently, the 2850 in a parentheses did not come back. — Preceding unsigned comment added by V255 Canis Majoris (talk • contribs) 16:44, 9 October 2016 (UTC)

This isn't about titles or winning. This is Wikipedia and it is only about presenting verifiable information in a neutral style. This list pushes the boundary in a great many ways, and continually risks presenting vague and contradictory information as a single concrete ranking. Please don't make it worse. Lithopsian (talk) 17:13, 9 October 2016 (UTC)

OK but consider that the radii they have now stays since the larger estimates can "NEVER" be confirmed as accurately as their current size. Plus why is NML Cygni still larger than VY Canis Majoris in the caption if NML Cygni is already smaller than Mu Cephei? Is it going to be replaced by WOH G64 or any other or should it remain? — Preceding unsigned comment added by V255 Canis Majoris (talk • contribs) 03:41, 10 October 2016 (UTC)

Dude, this picture was done when NML Cyg was still 1,650. Now it was ~1,160 something. It's just like a took a picture of a destroyed Germany in World War 2, and you reacted why Germany doesn't look like that anymore in 2016. Times change. And on the radii, yes. We only base it on the authors. The authors are the ones who solely have the authority to place sizes. We just report it. SkyFlubbler ^(talk) 10:21, 5 November 2016 (UTC)

Semi-protected edit request on 10 December 2016

Change 'Near the bortder with Andromeda.' to 'Near the border with Andromeda.' by XX Persei

No citation needed unless you want dictionary.... 86.191.30.81 (talk) 11:31, 10 December 2016 (UTC)

 Done! Thanks for pointing that out. regards, DRAGON BOOSTER ★ 11:52, 10 December 2016 (UTC).

Contradiction

"File:Comparison of planets and stars (sheet by sheet) (Apr 2015 update).png" says that NML Cygni is larger than VY Canis Majoris, but the "List of largest stars", along with the respective articles, say the opposite. ZFT (talk) 07:25, 5 January 2017 (UTC)

Hello! I created a new image of this article. Red Planet X (talk) 21:19, 7 January 2017 (UTC)

Semi-protected edit request on 28 February 2017

To create a list of well known stars. Add Sirius, Pollux, and Arcturus to the list. 2604:2D80:882C:FF39:A095:71A8:4A54:2793 (talk) 21:50, 28 February 2017 (UTC)

This page is for a list of the largest stars, not well known stars. Stickee (talk) 22:48, 28 February 2017 (UTC)

Significant figures in lead.

In the lead, the radius of the sun in kilometers is listed with 4 sig figs, but in miles with 6 sig figs.

This should be corrected, right? 8.40.151.110 (talk) 00:32, 4 March 2017 (UTC)

Recent edits and NML Cygni

Niyet' has been editing size for NML Cygni to be 1650 R_☉, both in this article and in NML Cygni. I have reverted edits altering the size of NML Cygni from 1,183 to 1,650 R_☉ as the source cited, De beck, shows 1,183 R_☉. However the article is wrong according to the source for NML Cygni. Regards— ~ The Omega Infinite CyberSpace Alpha X 16:21, 22 May 2017 (UTC)

1430 solar radii

I had to change KY Cygni back to 1420 solar radii if you don't mind. How the heck did it get 1430 solar radii and Wikipedia let it remain that way? First of all, there is no evidence of that slightly changed size and secondly, when I went inside the page, it says 1420 solar radii. — Preceding unsigned comment added by V255 Canis Majoris (talk • contribs) 01:46, 29 May 2017 (UTC) New Sizes: (2017)

Relations between Solar radius and Orbital radius of planets

Solar radius(R) = 6.96 × 10⁵ km.

Astronomical unit(AU) = 1.49597870691 × 10⁸km = 214.9 Solar radius.

List of orbital radius of planets

Planet	(AU)	solar radius = 1.0	example stars
Mercury	0.31 - 0.47	66 - 100	Rigel(78)
Venus	0.73 - 0.73	156 - 158
Earth	0.98 - 1.02	211 - 219	Deneb(203)
Mars	1.38 - 1.67	297 - 358	Alpha Herculis(264-303)
Outer limits of the Asteroid Belt			Antares(883)
Jupiter	4.95 - 5.46	1064 - 1173	Betelgeuse(1180) VV Cephei (1050-1900) VY Canis Majoris (1420)
Saturn	9.02 - 10.05	1898 - 2110	UY Scuti (<1900)
Uranus	18.29 - 20.10	2595 - 2930
Neptune	29.81 - 30.33	3714 - 4119

--Niyet' (talk) 03:49, 25 June 2017 (UTC) Niyet'