Talk:List of largest stars

I cleaned the list

Hi, I have "reset" the list due to it being way too messy, I know it may seem controversial, but it is the right thing to do at this point. Nussun05 (talk) 16:23, 24 September 2021 (UTC)

Note [b] needs a rewrite or further explanation; it's not immediately obvious that "SBL" = Stefan–Boltzmann law, the {{expand list}} already gives the "will be expanded" disclaimer, what happens if/when we start using Gaia data, etc. I guess I'm not even sure I understand the point of the note. Primefac (talk) 15:35, 26 September 2021 (UTC)

Gaia distances are known to sometimes be unreliable, especially for red supergiants and other luminous stars, so I'm excluding them until a consensus has formed for what Gaia parallaxes are reliable for this use case. Nussun05 (talk) 16:40, 26 September 2021 (UTC)

Just no. I haven't followed all the changes here over the last few months, but the current table is based altogether too much on original research. Excluding all radius calculations based on the most common method of determining stellar parameters is not for you to decide. If you have a reliable source (more reliable than the hundreds of published papers using the method!) that says SFB is bogus for this situation, then you can think about doing this. Otherwise, you just have to quote what the physicists have decided is fit to be published. Likewise, there is nothing so fundamentally flawed about Gaia distance determinations that we should be censoring any source that uses them. Much pre-Gaia work is based on methods with their own flaws, and we will struggle to filter out what is OK and what is not. Luckily, we have a good method: if it is published in a peer-reviewed journal then we can use it. Of course, basing our own Wikipedia calculations on data such as a Gaia parallax and something published elsewhere such as an angular radius is WP:SYNTHESIS anyway, so no doubt some pruning is a good idea. Lithopsian (talk) 17:46, 26 September 2021 (UTC)

I'm not excluding them, I'm planning to add them later just to keep the list simple for now, since it will take research to decide all SBL radii to use. Nussun05 (talk) 18:43, 26 September 2021 (UTC)

It is okay for me. Has there been any news on ST2-18's Gaia DR3 parallax?The Space Enthusiast (talk) 23:31, 26 September 2021 (UTC)

Its Gaia parallax is still negative/too small in EDR3, which means it's unusable. Nussun05 (talk) 06:16, 27 September 2021 (UTC)

I've inserted a note into the list section mentioning the recent edits. Hopefully in the upcoming weeks/months we can add stars with reliable sources (I think that recently (namely over the last year) too many new stars were added that may or may not have been dubious. I feel cleaning the list was a good decision and now we can work to build it up again!

Okay.-The Space Enthusiast (talk) 09:28, 27 September 2021 (UTC)

Added the L/T_eff estimates, obviously something has to be done because several values (like V354 Cep), are outdated. Nussun05 (talk) 13:16, 27 September 2021 (UTC)

The only Gaia criteria we have atm is astrometric noise significance below or equal to 2, so that's what I'm gonna use for the time being. Nussun05 (talk) 13:17, 27 September 2021 (UTC)

Semi-protected edit request on 27 September 2021

The list was trimmed though that means a lot of the latest information and sources have been cut off. Some of the stars are still stated to be larger than any on the trimmed list and the list ignores many updates. Some items are up to date but many of the other up to date items have been trimmed off.

The list was better before it was trimmed and was based on as much up to date information as possible. Ghkf (talk) 10:37, 27 September 2021 (UTC)

It really wasn't, a lot of stars were calculated from properties without really thinking about if the parameters are even reliable.

Declined. Although I agree with the sentiment, no specific edit request has been made. See WP:ER for details of how to submit an edit request. Lithopsian (talk) 10:53, 27 September 2021 (UTC)

How do you agree with that? Have you even seen the state of the list before it was reduced? Nussun05 (talk) 11:04, 27 September 2021 (UTC)

I really think we should start fact-checking the previous list version’s stars, including Stephenson 2-18. I would suggest starting from the most inaccurate ones from the previous list, but it is up for you to decide.-The Space Enthusiast (talk) 12:33, 27 September 2021 (UTC)

It's not really about fact-checking, obviously the radii present in the old list are stated in the paper, or at least the parameters to calculate a radius. Nussun05 (talk) 13:07, 27 September 2021 (UTC)

Uncertanties in many things to discover

Well we know stars exist including large ones, though while we're uncertain about some and their sizes, we view their properties as uncertain, but in reality there are always new things to find out about and only time and technology will tell. There are likely to be more factors in stellar properties than what we already know or understand. New discoveries can change our understanding forever. We never really know what's out there. Just like how we thought Earth was the center of everything until later technology including the telescopes (like Galileo's for example) helped us realize we're not the center, but moving in a system and we learned our Solar System moves around our Milky Way which in turn moves across the universe and there's so much more in the universe than we ever observed or know. New discoveries can make us rethink things and even change theories and anything can break the boundaries of physics (like black holes for example). Plus for example, since the stellar model size limit is only theoretical, there's no guarantee the models are accurate and like I said, new discoveries can change the way we think and view stars and other stuff. Plus it's always good to keep things up as we're always on the updates with stuff like stars. Remember when we even found galaxies that are far larger than we once thought galaxies would get? — Preceding unsigned comment added by Ghkf (talk • contribs) 16:14, 27 September 2021 (UTC)

Not to be rude, but... what's your point? Primefac (talk) 16:37, 27 September 2021 (UTC)

This method isn't gonna work

While I do think it's best to use papers where radii are stated, certain stars would then have radii already known to be out of date (like V354 Cephei), but we wouldn't be able to change them. So my suggestion is that we are allowed to calculate radii as long as we are cautious about the values used to calculate it. Nussun05 (talk) 05:37, 28 September 2021 (UTC)

But what do we mean by cautious?-The Space Enthusiast (talk) 07:00, 28 September 2021 (UTC)

We should check if the values are reasonable given known limits, and also the accuracy of the method used to calculate luminosity/temperature or distance/angular diameter. Nussun05 (talk) 07:06, 28 September 2021 (UTC)

Where are WOH G64, RW Cephei, NML Cygni, EV Carinae, RSGC1-F01, HV 888, and Stephenson 2-18? Will they return? V255 Canis Majoris (talk) 07:55, 28 September 2021 (UTC)

WOH G64 and HV 888 is extragalactic, and the other's radii are not stated in the paper. Nussun05 (talk) 08:57, 28 September 2021 (UTC)

Be patient, because Nussun removed them because their radius was based on the Stefan-Boltzman law (I might have botched that, forgive me for my mispelling.)-The Space Enthusiast (talk) 07:59, 28 September 2021 (UTC)

Well, don't forget we have {{List of largest stars row}}. Primefac (talk) 10:40, 28 September 2021 (UTC)

I know we do, I'm working on listing some manually calculated radii in the pending additions page [1] Nussun05 (talk) 11:10, 28 September 2021 (UTC)

Semi-protected edit request on 29 September 2021

New Largest star 'Stephenson 2-18' with solar radii of 2150 to be added Alexxking (talk) 20:55, 29 September 2021 (UTC)

 Not done: please provide reliable sources that support the change you want to be made. ScottishFinnishRadish (talk) 20:58, 29 September 2021 (UTC)

 Not done: Just no, that size isn't reliable at all. Nussun05 (talk) 04:47, 30 September 2021 (UTC)

There isn't a largest star. The large stars on the list are almost entirely in our galaxy, including the famous VY Canis Majoris. We don't know the sizes of the stars in the countless other galaxies in our possibly infinite universe, and we would most likely not reach them, so we have no way to know their size. The largest stars also pulsate, because of events inside the star, as their cores run out of hydrogen and fuse helium instead. Their outer layers become ill-defined as well. This makes finding a largest star very hard, if not impossible. I hope you understood my point.-The Space Enthusiast (talk) 08:15, 30 September 2021 (UTC)

Exactly! That's why I suggest to rename the page to "List of largest known stars". Nussun05 (talk) 09:13, 30 September 2021 (UTC)

Title and consistency

If this list is no longer going to consider stars outside of our galaxy, then I would suggest renaming the article to "List of largest stars in the Milky Way" or something else along those lines.

I've noticed some consistency issues with the latest version. Several stars have been removed because their size estimates are heavily disputed, but the same is true for UY Scuti with some estimates putting it at less than 1000 solar radii. V354 Cephei and Mu Cephei are most likely under 1000 solar radii as well. All yellow hypergiants seem to have been removed despite some of them being estimated to be larger than some red supergiants. Even using conservative estimates, Rho Cassiopeiae and V382 Carinae (and possibly V509 Cassiopeiae) would easily make the list. There are a few other issues (the 2850 solar radii estimate for KY Cygni is extremely unlikely, same goes for the 1940 solar radii estimate for PZ Cassiopeiae, etc.). It doesn't make sense to me to include some dubious or disputed size estimates but not others and I'm really not sure why yellow hypergiants don't seem to be considered at all now.

I understand the list is being reworked so I just thought I'd give some feedback. --Carnifex33 (talk) 07:21, 30 September 2021 (UTC)

It's coming later, I didn't add any yellow hypergiants to prevent the list from becoming messy again. KY Cyg and PZ Cas' upper size estimates obviously aren't accurante, that's why they're in parentheses. Nussun05 (talk) 08:27, 30 September 2021 (UTC)

I agree that V354 Cephei is likely below 1,000 Rsol, it's just there's so far no way to add it without violating WP:OR or using less accurate luminosity estimates. Nussun05 (talk) 08:29, 30 September 2021 (UTC)

The list will probably get extragalactic stars later. Nussun05 (talk) 08:30, 30 September 2021 (UTC)

Why is V354 Cephei in 1520 solar radii when its radius in its article says 685 solar radii? The size doesn't seem convincing.

Ikr, it's way too big, I would use the 685 solar radii but it's based on a Gaia parallax with too much astrometric noise, even the page says so. Nussun05 (talk) 18:30, 30 September 2021 (UTC)

So what size do you plan to give it? And what about UY Scuti's size? V255 Canis Majoris (talk) 19:17, 30 September 2021 (UTC)

Not really sure yet, there aren't many sources that give a size to V354 Cep. The Mauron et. al. one sadly does not contain a temperature. UY Scuti's estimate might shrink in the future. Nussun05 (talk) 19:50, 30 September 2021 (UTC)

If the sizes of V354 Cephei and UY Scuti are not certain, is it really necessary for them to stay in the list for the time being since other stars like WOH G64, NML Cygni, RW Cephei, and the others have not returned yet? — Preceding unsigned comment added by V255 Canis Majoris (talk • contribs) 14:08, 3 October 2021 (UTC)

WOH G64 and NML Cygni can be found in the pending additions. RW Cephei currently does not have a known accurate radius estimate. Nussun05 (talk) 17:11, 3 October 2021 (UTC)

Add some pending additions

I think the manually calculated list is getting ready to be merged, however the Miras with radii stated should not be included yet. Nussun05 (talk) 05:15, 1 October 2021 (UTC)

The future of the list

Okay so, when extragalactic stars get added, I suggest we either make separate lists or make the rows have different colors based on galaxy. Nussun05 (talk) 07:51, 1 October 2021 (UTC)

No colours, per ACCESS issues. Based on previous versions of the page, I would not be opposed to different tables for different galaxies, or at the very least Andromeda, Triangulum, and the LMC (and a fourth for 'other'). Primefac (talk) 11:35, 1 October 2021 (UTC)

Don't forget about the Small Magellanic Cloud. Nussun05 (talk) 19:22, 1 October 2021 (UTC)

There were only 11 in the SMC, wasn't sure how small we wanted to make the individual tables. Primefac (talk) 19:33, 1 October 2021 (UTC)

Perhaps grouping both magellanic clouds would be sufficient? And also grouping M31 and M33, and all other galaxies as a separate category. Nussun05 (talk) 17:47, 2 October 2021 (UTC)

Help me add more stars

I am currently just adding random stars that come into my head, I would like it if someone could suggest any more stars (above 200 R_☉) that I could add. Nussun05 (talk) 14:40, 11 October 2021 (UTC)

What methods should be counted?

How should we define the method list? Obviously L/T_eff and AD make sense to include, but what about the rest of them? Nussun05 (talk) 10:40, 12 October 2021 (UTC)

Um... if they're used, they should be in the list? For example, ight now I know AM (atmospheric) isn't used, so it's kind of pointless to have it in the list; I was going to remove it just now but I figured if you were still doing big updates to the lists I wouldn't get in your way if there were values using it that would then cause it to be re-added. Primefac (talk) 10:42, 12 October 2021 (UTC)

AM was used for a star I had plans to add to the pending additions, but decided against it. Nussun05 (talk) 10:51, 12 October 2021 (UTC)

My big question is do we only use methods used for calculating radius itself, or methods for the values used in the L/T_eff and AD calculations? For the former case it seems like only L/T_eff, AD, and sometimes SED qualify. The stars that don't use those methods according to the list don't have it clearly stated in the paper(s) that the star uses L/T_eff or AD. Nussun05 (talk) 10:56, 12 October 2021 (UTC)

Hrm, interesting point. We want to say at a minimum (for example) that they used luminosity and temperature to calculate radius, but do we necessarily need to say (again for example) that they used Spectral line ratios in order to determine that temperature? My immediate thought is no, mainly because we will likely end up making things too complicated. I mean, do we really care how they got T or L? Primefac (talk) 11:26, 12 October 2021 (UTC)

I know, but it is hard when the paper doesn't state how they determined radius in any clear way. A solution to this problem is to assume a radius was calculated using L/T_eff if the paper doesn't mention anything about an angular diameter value, and if said value was used in the radius calculation. Nussun05 (talk) 11:38, 12 October 2021 (UTC)

If they are calculating the radius and don't give a method, then I would mark that as either "unknown" or "not given", but we should not be assuming any particular method was used. Primefac (talk) 11:44, 12 October 2021 (UTC)

Sure, maybe we can make them blank as I've already done for a few stars? Nussun05 (talk) 12:07, 12 October 2021 (UTC)

Uhhh...

Recently User:SpaceImplorerExplorer downgraded the extreme red hypergiant star VY Canis Majoris down to 605 solar radii. While he said that the 600 solar radii estimate was newer, it was published in the 2000's but the oft-quoted 1,420 solar radii estimate was published more recently, published around 2012 or 2013. I won't revert his edit just yet, because it might result in an edit war. What do all of you think?

P.S.: I believe the newer and larger estimate is more reliable. --The Space Enthusiast (talk) 23:50, 3 November 2021 (UTC)

I think it should remain as a range (605 — 1,420±120 R_☉) since it is hard to tell which estimate is more reliable. SpaceImplorerExplorerImplorer (talk) 12:13, 4 November 2021 (UTC)

The list was ruined once again

The point of resetting the list was to keep it clean and relatively undisputed. But now people are adding back unreliable estimates such as those from the TESS input catalog? What is going on? nussun (talk) 09:41, 29 November 2021 (UTC)

I really don't know...You might want to ask User:SpaceImplorerExplorerImplorer as he is the one adding the estimates (The list was edited only by him in the past week). — Preceding unsigned comment added by The Space Enthusiast (talk • contribs) 10:36, 29 November 2021 (UTC)

There's also the source that CD Hydri is from, where that star and all other stars have meaningless radius estimates, since the errors are bigger than the values themselves. nussun (talk) 11:00, 29 November 2021 (UTC)

Oh my.--The Space Enthusiast (talk) 11:04, 29 November 2021 (UTC)

I do not know what the uncertainty is in the TESS Input Catalogue although I do see with the one of CD Hydri. So I would change the name of the page to List of possible largest known stars to already note some uncertainty in the beginning. SpaceImplorerExplorerImplorer (talk) 15:10, 29 November 2021 (UTC)

Once, again VY Canis Majoris and Stephenson 2-18 have been added.--The Space Enthusiast (talk) 09:33, 30 November 2021 (UTC)

I've removed them, and I don't know why that person added it since it is unreliable.SpaceImplorerExplorerImplorer (talk) 09:59, 30 November 2021 (UTC)

Don't remove Vy Canis Majoris' estimate, because that is really reliable.--The Space Enthusiast (talk) 10:20, 30 November 2021 (UTC)

I didn't mean VY CMa's estimate I was only talking about St2-18 that was unreliable also adding that 1,420 ± 120Rsun estimate is just duplicating since it is already as a range from 605 – 1,420 ± 120Rsun. And both estimates are reliable as well.SpaceImplorerExplorerImplorer (talk) 10:43, 30 November 2021 (UTC)

Also in the paper that said ~605Rsun for VY CMa it said that it is certainly not in hydrostatic equilibrium so even if it is much different to the 1,420Rsun that is just because it is not spherical and it is also a variable star.SpaceImplorerExplorerImplorer (talk) 10:57, 30 November 2021 (UTC)

If UY Scuti's size is above the theoretical limit and isn't accurate, what is it still doing on top of the list? V255 Canis Majoris (talk) 23:12, 18 December 2021 (UTC)

It is not necasserily inaccurate and the lower scale radius is not so much larger than the theoretical limit although I would say it is probably between 1,000 R_☉ and 1,300 R_☉ and that it is hard to tell the radii of any red supergiant stars because their dust clouds can disturb observations so many of the stars on this list (above ~1,200 R_☉) are probably much smaller (eg. UY Sct, VY CMa (A?), AH Sco, S Per). SpaceImplorerExplorerImplorer (talk) 07:57, 19 December 2021 (UTC)

WP:OR and WP:SYNTHESIS. We shouldn't say it is larger than any theoretical limit without a specific reference to back up that claim and we certainly shouldn't be changing or omitting particular well-sourced values just because we have our own reasons for thinking they are invalid. There are good reasons for thinking this particular case is just plain wrong, but being larger than some extremely vague theoretical value is the least of them. Unfortunately until there is something in print that we can refer to as either a newer and better value or a reason to not use the old one, we 're stuck with it. Lithopsian (talk) 14:28, 19 December 2021 (UTC)

Inclusion criteria

I'm curious as to why this list now includes stars down to 200 solar radii. In the past, the limit was 700 or 1000 solar radii. SevenSpheresCelestia (talk) 19:15, 19 December 2021 (UTC)

I believe when the list was pruned it resulted in all reasonably-sourced values being re-added since we were no longer at a bazillion stars with 1000+ R_☉. I'm up for re-opening the discussion though. Primefac (talk) 13:20, 20 December 2021 (UTC)

Indeed, most of the loads of stars above 1,000 R_☉ were extragalactic stars with unreliable sources and with calculated radii, and for many other reasons. It is just not practical to have loads of unreliable references of stars, which made the list very messy. SpaceImplorerExplorerImplorer (talk) 10:05 21 December 2021 (UTC)

Is it practical to have loads of stars between 200-700 solar radii? SevenSpheresCelestia (talk) 20:20, 21 December 2021 (UTC)

In my opinion, no. Even in the "old days" (like, 2017) there were only about two dozen stars <700 R_☉ listed. We raised the floor to 1000 when the list got huge, but we don't need dozens of not-actually-all-that-large stars listed. Primefac (talk) 13:09, 22 December 2021 (UTC)

I feel that the stars used 'for comparison' exceed the stars this list is actually meant to catalogue. Surely we could remove some of the stars between 200 and 700 solar radii?PNSMurthy (talk) 05:22, 24 December 2021 (UTC)