Talk:UY Scuti

Distance, luminosity and parallax

I've created this article. I am just a 13 year old boy, and I just get my information from SIMBAD. Please help me add some information about UY Scuti's distance, luminosity, and parallax, if you have any information about it. Thank you! Johndric Valdez (talk) 12:07, 11 September 2013 (UTC) :)

Error in size determination

I've just turned to the list of largest known stars, and found out that UY Scuti has errors in its size determination. I fear that maybe my information might had just don't make it contrary to current ideas. You can edit my article if new results were found to its size. Johndric Valdez (talk) 12:07, 11 September 2013 (UTC)

Largest known star?

At an astonishing size of 2.38 billion kilometres, or 1,708 solar radii, UY Scuti has now taken the place NML Cygni held for more than a year. Some websites are now reporting UY Sct as largest known star, and it was true at all, based on observations.

But according to a smart, good friend under the name Lithopsian, about a dozen stars were fighting for the throne. And it was true, candidates were VV Cep A, PZ Cas, RW Cep, KY Cyg, Wd 1-26 and WOH G64. And Lithopsian has provided a journal on the List of largest known stars that states UY Scuti has erroric scheme of estimate. Based on this data, if we relied on this, more candidates will follow. The reason that I've put only "one of the largest known stars" is because of what Lithopsian said that nothing has really changed, lots of stars are still competing for the throne. So don't start up shouting UY Sct as largest, there are erroric possibilities in size estimates, with uncertain predictions. If you don't understand then just ask Lithopsian, because he's the expert.

To Lithopsian, please add a reliable journal concerning this. I need your help. ==Johndric Valdez (talk) 06:14, 10 October 2013 (UTC)==

UY Scuti is truly the king of stars, with candidates including PZ Cassiopeiae, VV Cephei A, VY Canis Majoris, KY Cygni, Westerlund 1-26, WOH G64, and NML Cygni. Nobody know who really is the largest star though, but it is best to say UY Scuti is the one. --Joey P. - THE OFFICIAL ^{(Visit/Talk/Contribs)} 05:58, 28 October 2017 (UTC)

Mass correct?

The mass is given as 32 times solar mass. That seems impossibly low. — Preceding unsigned comment added by 94.226.172.196 (talk) 21:01, 15 December 2013 (UTC)

Why impossible? Red supergiants simply don't come much more massive than that. The mass is of course only an estimate based on stellar models that most closely reproduce the observed characteristics, but the models have been verified against other methods such as binaries and they won't be hugely wrong. Lithopsian (talk) 21:10, 15 December 2013 (UTC)

Supergiant or hypergiant?

UY Sct's spectral luminosity class and absolute magnitude fit it to become a hypergiant. Is this star a hypergiant or just a down-ranking supergiant? ==Johndric Valdez (talk) 12:06, 29 January 2014 (UTC)==

Hypergiant is not a term with a fixed definition. Specific to this case, red supergiants do not receive the O or Ia⁺ luminosity class because their spectra never show the relevant features, so hypergiant applied to an M star is simply a reflection of sufficiently high luminosity to place the star at the limits of stability, resulting in turbulence and high mass loss. The stability limit for all cool stars is placed at around M_V -9.5. Lithopsian (talk) 12:35, 29 January 2014 (UTC)

In the first paragraph in the article of VV Cephei, it states there that "Although VV Cephei is an extremely large star showing high mass loss and having some emission lines, the spectral luminosity class and absolute magnitude do not qualify it as a hypergiant." VV Cephei A has the spectral type M2Iab, which is not for a hypergiant. Some other stars, like VY CMa and NML Cyg all have spectral class Ia, and UY Scuti has too. Also, it is stated that VV Cephei A does not have enough luminosity, being 200,000 times that of the Sun. So far I haven't seen any hypergiant star below 250,000 times the Sun's luminosity (like VY CMa and NML Cyg both having 270,000). But UY Scuti hs 340,000, so it may fall into the class of hypergiants. ==Johndric Valdez (talk) 14:18, 30 January 2014 (UTC)==

I refer you to the definition section of the hypergiant article. It says all there is to say really and I can't add to it (especially since I wrote it!). Under that definition VV Cep fails completely to be a hypergiant. You can argue about whether any red supergiant should be called a hypergiant or not, but the term has been commonly used by astronomers, some of whom are as keen on populist hyperbole as anyone else, and by the press release folks who are paid precisely to attract the attention of the public with fancy words like hypergiant whether they're appropriate or not. On Wikipedia we should at least be internally consistent and any star classified here as a hypergiant should fit the definition given in that article. If you feel the definition is wrong then feel free to change it, supported by suitable references of course. Lithopsian (talk) 15:14, 30 January 2014 (UTC)

Kick Up A Fuss, Big Error Deals

I am going to bring back what I've said above. Lithopsian was right. Almost all pages concerning the largest stars in the Internet only base their claims on here in Wikipedia. One edit here and hundreds (thousands?) will claim it. Too bad they only claim what they see here (like the table in the list of largest known stars page) and do not study those refs.

In just a matter of few months, I was surprised how many reports in the Internet claim UY Scuti defeated NML Cygni in the first place when the fact is UY Scuti is the more likely to be defeated. Simply this claim arouses because people only look at star rankings, not the references. So now, I would like to request, what about changing UY Scuti's size from 1,708 ± 192 solar radii to 1,515-1,900 solar radii (like on AH Sco. Lithopsian changed it from 1,411 ± 124 solar radii to 1,287-1,535 solar radii) simply because people claim what is unlikely to be the largest known star.

Look, NML Cygni's estimate is very precise, 1,650 solar radii, no more nor less. We can't figure it out on UY Scuti; we are not sure about the size, yet the Internet claims because it was in the highest, not understanding the refs. If we did the 1,516-1,900 figure, we will push him to 4th place, below VX Sgr, and will rethrone NML Cygni. We must do that because I don't want people to claim the largest star as a star with errors, rather a star with a sureball estimate. Johndric Valdez (talk) 14:22, 18 February 2014 (UTC)

I'm not comfortable claiming either of these stars is "the largest". Certainly not based on a single paper (each) using different methodologies and where the likely errors are much larger than the differences between the two stars. But if someone wants to have a table of the largest stars then one star will have to be at the top and it will have to be the one with the largest reported radius, reported by us in as unbiased and consistent a way as possible, not using our own preferences to get one star or another to the top, however well intentioned that might be.

It isn't fair to say that NML Cygni has a radius of 1650, no more nor less. That is a number that doesn't even appear in the referenced paper. I know because I am the one who typed it in to Wikipedia and I was uncomfortable when NML Cygni ended up at the top of the list, even more uncomfortable when it got featured on the Wikipedia home page because of it. That number is merely implied by the temperature and luminosity given in the referenced paper, both of which have margins of error. I simply didn't feel it was appropriate to quote a margin of error on the radius, just quoting a calculated radius was as far as I was prepared to push "own research". Also, for UY Scuti it isn't fair to say that 1,708 ± 192 is the same as 1,515-1,900. The margin of error quoted in scientific papers has a very specific meaning, and it doesn't mean that the figure is definitely somewhere between two numbers. It could be larger or smaller, but with decreasing likelihood. I quote a range of values where different papers quote different values. I rarely include a margin of error simply because most people will misinterpret what it means. For these two stars specifically, one radius measurement is based on the assumption of a circular disk of a uniform effective temperature leading to a given luminosity, assumptions which certainly aren't true. While the other bases the radius on the observed sizes of the disk at certain wavelengths based on observations of water and carbon monoxide (combined with an assumed distance). The two papers just aren't measuring the same thing. The UY Scuti number is actually more rigorously derived, although still almost certainly too high. In a range of measurements of objects all approximately the same size (as extreme red supergiants almost certainly are) with random observational errors, the star found to be largest is simply the one with the largest error.

All of which makes a table, and especially a single largest star, even more meaningless. Is 1500 bigger or smaller than 1400-2400? Is 1500±500 bigger or smaller than 1400? Maybe we should put KY Cygni to the top (or W1-26) since it has the largest quoted radius at 2850, but that number is almost certainly wrong, even the authors of the paper say so. So I think we should only quote the numbers we get from the references, and then order the table in accordance. Lithopsian (talk) 14:58, 18 February 2014 (UTC)

Maybe we should take it to those "list of (superlative) stars" articles - problem is laypeople love those sort of facts so we can try and make them as buffed as possible. Cas Liber (talk · contribs) 20:34, 18 February 2014 (UTC)

Please do not calculate a diameter and put it into Wikipedia; that is entirely your own research.At least I try (talk) 18:23, 6 May 2016 (UTC)

What does UY mean?

What does UY mean? — Preceding unsigned comment added by 82.139.81.0 (talk) 20:36, 12 March 2014 (UTC)

Variable stars are named with a captial letter starting with R and the constellation name, for example R Tauri. When there are more variables than letters, two capital letters are used, for example AB Cygni. Lithopsian (talk) 20:48, 12 March 2014 (UTC)

Additionally, if the variable star is the 355th discovered in the constellation, it should be named with V and the number. Example: V766 Centauri, V567 Cygni, etc. Johndric Valdez (talk) 13:52, 21 March 2014 (UTC)

Distribution Error

The article says that stars like these occur on average once per 1500 cubic light-years. This is obviously meant to mean something like one star per a volume equal to a cube 1500 light-years on a side (or perhaps a sphere of radius 1500 light-years), but it could also be misinterpreted as one star per 1500 ly^3, which would space them on average 11-12 light-years apart. 2620:72:0:52F:D50E:F71C:90F6:37E7 (talk) 17:12, 30 September 2014 (UTC)

Someone misinterpreted the Math. It is really a cube 1500 light years across and not "1500 cubic light years". SkyFlubbler (talk) 12:27, 10 October 2014 (UTC)

Someone fix this, I am not an expert, but 25 stellar radii is NOT 400 AU!!!

Scuti is surrounded by a thick ionized nebula extending out to 25 stellar radii (400 AU) and with four times the mass of the sun. The disc may be gases ejected by UY Scuti as it passed through the yellow evolutionary void a few thousand years ago. — Preceding unsigned comment added by 2601:D:2383:DAC:7473:D876:F7E1:7DE (talk) 09:56, 20 January 2015 (UTC)

UY Scuti's diameter (maximum):

2.644 billion km x 25 = $66,12$ billion km

$66,120,000,000/149,800,000$ (1 AU) $=442$ AU (rounded)

Thus, 25 UY Scutian radii would be 442 AU. The diameter of the ionized nebula would be ~884 AU. --Joey P. - THE OFFICIAL ^{(Visit/Talk/Contribs)} 04:55, 26 October 2017 (UTC)

Image

This image looks trollish. Could it be real? Hubblesite.org has no mention of observations of UY Scuti. --79.166.76.26 (talk) 07:46, 1 April 2015 (UTC)

I agree, this image is not a Hubble image as far as I can tell from google image search and searching on the Hubble site, could someone more advanced in editing than me examine and take it down if it's not an actual Hubble image of the star.73.254.181.101 (talk) 02:32, 7 January 2018 (UTC)

In what galaxy?

Can the article please identify the galaxy in which the star resides? Thanks! --Lbeaumont (talk) 02:44, 8 May 2015 (UTC)

It's just 9,500 light years away, so it's in the Milky Way. SkyFlubbler ^(talk) 16:08, 28 May 2015 (UTC)

On improving the article...

I'm passionate about improving this article to GA. I'd like Oshwah and Eat me, I'm an azuki to join me.. Would you? Thanks and regards—UY Scuti ^Talk 11:49, 15 January 2016 (UTC)

I would be delighted to. How can I help?—azuki (talk · contribs · email) 11:51, 15 January 2016 (UTC)

I highly disregard this. The only source that we can get for UY Scuti is by Torres 2012, and even that one is not complete. GA articles must have multiple references and massive consorted data, which is not yet available for UY Sct.

UY Scuti did not reached the fame enjoyed by VY CMa more or less nine years ago, making information about it relatively little. And in all honesty, the only thing that makes UY Scuti remarkable is its size. It was not discovered before 1850 nor a very special star to change the laws of stellar evolution. All that it has is that it is a large star and nothing else.

I tried to find any other reference in arXiv, but none has appeared. If you can improve it, do it and point out new thoughts, supported by references of course. SkyFlubbler ^(talk) 13:16, 15 January 2016 (UTC)

I'll go through today and make a formatting pass-through, and a copy edit of the article. There are some things that can be changed that will be good improvements, and give the article a huge boost. Let's get this article to GA status! :-) ~Oshwah~^{(talk) (contribs)} 13:36, 15 January 2016 (UTC)

@SkyFlubbler: thanks for providing your insight on this.. And I agree sources are rare here.. We should've done the math before. (But I'll keep this on my watch and improve it whenever I could) Thanks and regards—UY Scuti ^Talk 18:17, 15 January 2016 (UTC)

I see no harm in tightening up the article. There aren't exactly hundreds of published papers on the star, but more than enough to demonstrate notability and back up an article. No reason why it couldn't be made a good article, although perhaps not the largest good article there's ever been. I plugged in some basic data today and corrected a few minor points in the text. Even the apparent magnitude was a couple of magnitudes out because it was a photographic instead of visual. Lithopsian (talk) 20:48, 16 January 2016 (UTC)

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Age?

Has the age of this star been determined?  If so, what is it?  If not, what factors prevent a proper determining of its age, and are there any potential scientific approaches being developed to determine its age?

Inclusion of answers to these questions would constitute an improvement to this article.

allixpeeke (talk) 12:28, 12 May 2017 (UTC)

UY Sct is around 5 million years old. You can quote me on that, although I'm not giving a margin of error ;) I'm not aware of any explicit publication of its age, although it is certainly "known" in the scientific community, subject to differences between models and determination of its physical properties. Arroyo-Torres includes an H-R diagram of evolutionary tracks, but does not mark the ages on the tracks. Picking a position on an evolutionary track is somewhat subjective, and likely was not considered reliable enough in this case to be published. The margins of error for the luminosity alone would suggest an initial mass anywhere from 25 M_☉ to 40 M_☉, with a consequent large difference in the current age. Lithopsian (talk) 13:22, 12 May 2017 (UTC)

"Inclusion of answers to these questions would constitute an improvement to this article."  allixpeeke (talk) 20:05, 15 June 2017 (UTC)

Hypergiant or not?

This article says UY Scuti is not classified as a hypergiant. The actual hypergiant article says it is. Which is it? 136.159.160.4 (talk) 18:54, 15 September 2017 (UTC)

Whichever you want :) Find good sources to support what you write. Random fanboy web pages are not good sources. Right now there is some commentary addressing the hypergiant question that is completely lacking inline citations, so almost anything you find would be better. Then don't be offended if someone else changes it and uses a different source. Just for the record, published scientific papers calling UY Sct a hypergiant are very thin on the ground, and the general thesis of the commentary is correct - ie. strictly there are no red hypergiants at all, just a few stars to which someone wanted to attach hyperbolae. Lithopsian (talk) 20:28, 15 September 2017 (UTC)