Talk:HR 5171

Proposed merge with HR 5171

According to User:Silvio1973, the HR page duplicated some of the content of the V766 page. IagoQnsi 18:01, 12 March 2014 (UTC)

The article should be edited to avoid name confusion. Wjfox2005 (talk) 17:20, 13 March 2014 (UTC)

Requested move

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: Moved. It has been stated that 'HR 5171' is more often used in the press. Nobody seems to have a strong objection to that name. My simple Google search found that HR 5171 has a lot more hits than V766 Centauri. EdJohnston (talk) 20:14, 7 April 2014 (UTC)

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V766 Centauri → HR 5171 – The recent media releases used the name HR 5171 for this star, not V766 Centauri. This indicates that the common name for this system should be HR 5171. 77.56.99.23 (talk) 10:14, 30 March 2014 (UTC)

I originally created this article, but I'm comfortable with changing the name. HR 5171 is the name probably most often used, and certainly is an older designation. Lithopsian (talk) 19:33, 30 March 2014 (UTC)

• Comment Press releases seem to say HR 5171 A; presumably the cool companion is "B" and the distant type-B companion has a different HR-number -- 70.24.250.235 (talk) 05:31, 31 March 2014 (UTC)
  • Actually the B-type companion is HR 5171 B. Not sure if the individual components of A have been assigned designations, they would presumably be Aa and Ab if this was done. 77.56.99.23 (talk) 06:29, 31 March 2014 (UTC)
    • It's rather surprising that a B-type star that's only 11kly away doesn't have it's own Harvard designation. -- 70.24.250.235 (talk) 07:15, 1 April 2014 (UTC)
      • Well SIMBAD lists the magnitude of the companion as 10.2 which is below the threshold for the Bright Star Catalogue. It's also something of a testament to the truly impressive nature of the yellow hypergiant - it is outshining a B0 supergiant by a factor of roughly 30 or so. 77.56.99.23 (talk) 18:53, 1 April 2014 (UTC)
• Hmm, it's tricky - alot of astronomical articles use the HD, HR or HIP numbers even when a star has a Bayer designation. I find the strings of numbers hard to remember sometimes and find the variable star designations much easier to process instantly, thus "V766 Centauri" is alot more accessible and memorable than the HR designation. That said, I am not sure how often it's used. Have been meaning to look through the references at SIMBAD to get a feel for numbers. I prefer "V766 Centauri", but if it is almost never used then the argument for it is pretty weak...Cas Liber (talk · contribs) 19:31, 1 April 2014 (UTC)
  • Both appear to be in use, although the HR number slightly moreso. As a result, and due to what Casliber mentions about accessibility, I don't have strong feelings either way on this move, as there's arguments to be made for both sides. StringTheory11 (t • c) 00:31, 2 April 2014 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

Downscale

I had to downscale HR 5171 back to 1 315 R☉, both on the article and List of largest stars for a few reasons if you do not mind. The main reason is that most sources say that HR 5171 is 1 315 R☉, and some people think of Wikipedia as an inaccurate encyclopedia, so it would not be a good idea for Wikipedia and most sources to have contrary values, especially for people who want to know what it is. Another reason is that if the upper value of 1 490 R☉, it would be a red supergiant, contrary to being a yellow hypergiant. Thank you. --Joey P. - THE OFFICIAL (talk) 06:39, 19 August 2017 (UTC) (Talk/Contributions)

We change articles based on sources, not opinion. People have used different calculations, and highlighting the differences illustrates the uncertainty around this. Cas Liber (talk · contribs) 10:08, 19 August 2017 (UTC)

I originally included both estimates in the starbox when the new paper was published, and some text in the body, but the article has been mangled considerably since then. The newer larger figure is surprising but not really incompatible with the older smaller one given the large margins of error. Both are fairly recent and based on good science. Web pages are poor sources for information like this, they are often copied from very old sources of from Wikipedia itself. Even books, one of the preferred Wikipedia sources, are unreliable because they tend to be so out of date in a field where instrumentation has developed so much in the last few decades. Lithopsian (talk) 10:59, 20 August 2017 (UTC)

@Lithopsian: HR 5171 A is probably a yellow hypergiant according to this image: https://en.wikipedia.org/wiki/HR_5171#/media/File:Potw1740a.tif. So it would be 1,315 R_☉ assuming it is a yellow hypergiant. If it is 1,490 R_☉, it would be rather a red supergiant/hypergiant than a yellow hypergiant. Wittkowski also gives a radius of 1,575 R_☉. So is the 1,315 R_☉ reliable/verifiable or 1,490 R_☉? ZaperaWiki44^{(✉/Contribs)} 12:29, 18 December 2017 (UTC)

Oh dear, the search for the "correct" answer. First, the image description does not declare it to be a yellow hypergiant, but describes the traditional classification as well as the newer terminology from Wittkowski et al. Second, semantics, even 4,290 K is pretty hot for a red supergiant and the spectral type is of course not remotely that of a red supergiant so to some extent they're just disagreeing with eachother for the sake of a headline. Similarly, the newly-calculated radii (or angular diameters, if you like) are all within the quoted margins of error of eachother; they are all modelling very similar observations in different ways and getting slightly different answers. Its worth remembering angular diameters and diameters derived from an effective temperature are not always directly comparable despite advances in the techniques of measuring Rosseland radii. Even allowing for the high reddening and unusual spectral distributions, the spectral/colour appearance is hard to reconcile with a very large diameter and consequent temperature nearer to 4,000 K than 5,000 K - I would like to have seen more discussion of this, because calling a K0 star a red supergiant needs some sort of justification beyond looking big. Lastly, HR 5171A is strongly photometrically variable beyond the modest eclipses, with the potential for temperature or luminosity changes over time, possibly even radius changes from pulsations or irregular mass loss. The Chesneau observations were made on one night (and a half) at multiple wavelengths, all providing fairly consistent result and consequent low margin of error. The Wittkowski measurements were over a longer period and were less consistent, no doubt in part because of the varying position of the companion, but easy to also imagine that there inherent changes in the appearance of the large star itself. Lithopsian (talk) 21:50, 18 December 2017 (UTC)

Intriguing - I think the best approach is to highlight all the data and how it was obtained, along with the margins of uncertainty and (hopefully) some papers that attempt to reconcile disparate results. I do think it is important to show uncertainty to readers. I have not done much reading on this star but it might benefit from having all the research in greater detail in the article. Cas Liber (talk · contribs) 01:04, 19 December 2017 (UTC)

I'm on it. Probably. Slowly. Lithopsian (talk) 15:57, 19 December 2017 (UTC)

The star isn't a contact binary

This paper [1] clearly states that the star being a contact binary is out of the question, however they do not rule out an unobserved companion. Please reword the article. nussun (talk) 16:17, 1 January 2022 (UTC)

In it's current state, the article seems to be a typical example of bad Wikipedia writing:

1. The lead rejects the contact binary hypothesis, on the basis of just one paper (van Genderen et al, 2019) but it accepts the 10-15 AU radius of the original theory (while van Genderen et al have reduced it to 3-5 AU).
2. The body of the article follows the contact binary model (Chesneau et al, 2014, see also Wittkowski et al, 2017) and the 3,6 kpc / 10-15 AU figures for distance and star radius.

Since there is no academic consensus on the matter, I think we should be more neutral (and more consistent). I will make an effort towards this direction, please correct me if I'm wrong.--Dipa1965 (talk) 20:08, 21 January 2024 (UTC)

We don't need to be the arbiter of which academic source is correct. I would just state both positions in the article, along with their sources. Praemonitus (talk) 01:08, 25 May 2024 (UTC)

Did I do well in incorporating information from van Genderen et al. (2019) into the body?

The source also includes missing information on the star's recent evolution as a yellow hypergiant, which I have not attempted to add. Yellow hypergiants are known to undergo repeated blue loops over several decades. –LaundryPizza03 (dc̄) 23:49, 13 June 2024 (UTC)