Talk:Westerlund 1-75

On 13 March 2023, it was proposed that this article be moved to Westerlund 1 W75. The result of the discussion was procedural close.

Feedback from New Page Review process

I left the following feedback for the creator/future reviewers while reviewing this article: Would you consider merging these newly created pages into the main article? They are all virtually identical and I don't see any notability independent from the main cluster..

Sam-2727 (talk) 15:53, 30 May 2020 (UTC)[reply]

Adding ping: MuCepheiBetelgeuse. Sam-2727 (talk) 17:04, 30 May 2020 (UTC)[reply]

I think so toPNSMurthy (talk) 03:08, 7 July 2020 (UTC)[reply]

This can be proposed formally using the {{mergeto}} tag and starting a discussion. If nobody opposes or if the result of the discussion is to merge then it will happen. Lithopsian (talk) 18:35, 22 October 2020 (UTC)[reply]

Different values

Sources:

Fok, Thomas (2012)
Arévalo, Aura (2019)

Distance (in kpc):

3.5 Fok, page 9, 11, page 38 Table 7

(4.35 ± 0.20) Arévalo, page 42

Luminosity:

10^4,83 Fok, page 11 (= 67.608)

0.33 ± 0.03 * 10⁵ Arévalo, page 45 Table 2.7 (= 33,000)
0.34 ± 0.03 * 10⁵ Arévalo, page 45 Table 2.7 (= 34,000)
0.57 ± 0.05 * 10⁵ Arévalo, page 45 Table 2.7 (= 57,000)

1.20 ± 0.14 * 10⁵ Arévalo, page 58 Table 3.5 (= 120,000)

Temperature (in K):

3600 Fok, page 38 Table 7

4000 Arévalo, page 54, 57 Table 3.4
4000 ± 100 Arévalo, page 58 Table 3.5

Radius (in R_☉):

668.42 not in Fok, but calculated based on the values given by Fok

722 ± 36 Arévalo, page 58 Table 3.5

1272 ± 85 Arévalo, page 46 Table 2.8
1303 ± 77 Arévalo, page 46 Table 2.8
1716 ± 98 Arévalo, page 46 Table 2.8

Mass (in M_☉):

20 Arévalo, page 60, 61 Table 3.6

Age (in Myr):

7.9 Arévalo, page 61 Table 3.6

--Agentjoerg (talk) 05:23, 6 July 2022 (UTC)[reply]

The mass is easy to address. It is an initial mass and not a current mass, so it can't go in the starbox. It could be included in the text though. You missed out some temperature values from Arévalo, table 2.3 on page 41. These values are discounted as unreasonable, but they are the source of the large radius values shown in table 2.8. There are also corresponding luminosities in table 2.7, strongly dependant on the temperatures and so also discounted. So I think we completely ignore all those unless we want to go into a very deep discussion in the text. The adopted temperature is 4,000 K, derived from the spectral line widths, vs 3,600 K from Fok. Take your pick, one is from spectral analysis, one from a DUSTY SED model. A lot of the other differences are down to distance assumptions: 4.35 vs 3.5 makes a big difference, about 50% on bolometric luminosity, 25% on radius. Despite the different methodologies, this almost entirely accounts for the difference in luminosity, with the rest coming from the difference in temperature. 3.5 kpc is a "compromise" distance between the kinematic distance derived in Fok and earlier larger distances by a variety of methods. 4.35 kpc is taken directly from a paper that calculated the orbit of W36; that is the only direct determination of a distance to Westerlund 1 and might be considered the most definitive. Or it might be considered just one of many distance determinations in the range of 3-6 kpc.

We might have to wait for Gaia's final data release and keep our fingers crossed that it can make sense of observations which clearly have a lot of scatter even though in theory it should be able to measure a useful parallax. Purely for fun, I've examined the Gaia DR3 parallaxes of a fair number of supposed cluster members and they are all over the place with considerable margins of error, but ranging from about 0.2 mas downwards, suggesting distances of 4kpc plus. It seems hard to reconcile them with a smaller distance or even with eachother without some systematic errors. A rough filter of all objects in the Westerlund 1 field (1-2′ with similar proper motions gives mostly small to very small parallaxes suggesting even larger distances than are generally assumed for Westerlund 1. It would take some serious analysis to derive a good distance out of them though. There has been such an analysis of Gaia EDR3 parallaxes (Beasor et al 2021), which includes a good list of earlier distance determinations, including several conflicting ones derived from the same Gaia DR2 data. Strangely, it doesn't mention the dynamical distance derived for W36. The EDR3 result is 4.12+0.66
−0.33 kpc. That's probably the distance we should put in the starbox, pending either a good parallax or some other definitive distance. The same paper derives luminosities by two methods and while it doesn't give a printed temperature, it does have an HR diagram showing an assumed temperature of around 4,000 K. Again, we could easily pick those values (maybe not the temperature) for the starbox. Lithopsian (talk) 14:54, 6 July 2022 (UTC)[reply]

Requested move 13 March 2023

The following is a closed 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 after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: procedural close. This isn't really a "no consensus" due to low attendance. Initial nominator now prefers a different name and should nominate all relevant pages for that together as a new RM. (closed by non-admin page mover) Elli (talk | contribs) 04:15, 22 March 2023 (UTC)[reply]

Westerlund 1-75 → Westerlund 1 W75 – Per discussion from Talk:Westerlund 1 W26#Requested move 9 February 2023. Regards—ZaperaWiki44^{(✉/Contribs)} 18:09, 13 March 2023 (UTC)[reply]

Changed my mind per Talk:Westerlund 1 W26#Comments after closure and Talk:Westerlund 1-243#Requested move 13 March 2023, should be moved to W75 (star) (since W75 exists in Wikpedia as a redirect to W74) as "Westerlund 1 W75" doesn't seem to be used anywhere either, except for sources copied from Wikipedia. However, Wd1-W75 has been used at least once by a 2022 paper. Regards—ZaperaWiki44^{(✉/Contribs)} 11:01, 19 March 2023 (UTC)[reply]

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.