Talk:Westerlund 1

Distance?

What's the correct distance? Or what's up with saying the cluster is 5 kpc away, yet extragalactic? Even if it were 5 kpc out of the Milky Way's plane, it would still be considered completely within the galaxy. —Preceding unsigned comment added by Jmacwiki (talk • contribs) 22:13, 30 May 2009 (UTC)

It's a galactic cluster, the first sentence is really saying that the only more massive clusters known are outside the local group. So this could do with clarification. The exact distance isn't known, but 5kpc is the current best estimate from both the yellow hypergiants (Clarke et al, 2005) and Wolf-Rayets (Crowther, 2006), I was going to add a bit about that Westerlund1 (talk) 05:56, 31 May 2009 (UTC)

Mass?

I have understood Omega Centauri (4 million solar masses) to be the most massive star cluster in the Galaxy (Mayall II in Andromeda is estimated as ten million solar masses.) We say this one is "the most massive compact young star cluster known in the entire Local Group of galaxies", which I suspect hinges on the qualifier "compact young". This strikes me a rather weaselly claim. It is also curious that it "will probably evolve into a globular cluster". Wwheaton (talk) 18:38, 16 October 2013 (UTC)

The mass of Westerlund 1

---Discussion copied here from personal talk page---

I think the statement about its mass might have come from here: http://www.dfists.ua.es/~ignacio/wd1_research.html - although this page only says it's the most massive young cluster in the Milky Way. This page (http://arxiv.org/abs/0711.1624) is for a paper co-authored by Ignacio Negueruela, who is responsible for the other page and it says Westerlund 1 is "among the most massive young clusters in the Milky Way". Perhaps this last statement could be included?VirtualDave (talk) 07:35, 9 June 2015 (UTC)

Probably. Someone got over-excited though. Even the (very old, in this context) web page only says "It is probably more massive than any other young cluster in the Local Group of galaxies." and that is an exaggeration of what they were prepared to put in a journal paper, which started as "likely to be one of the most massive young clusters in the Local Group" in 2003 and moderated to "among the most massive young clusters in the Milky Way" by 2008. If it is in a peer-reviewed journal and not refuted by more recent research then it can go in the article. We should be careful not to exaggerate, which usually means not relying on blogs, web pages (even of professional researchers!), and press releases, and not to state as fact information which is disputed or obsolete. Here's a fairly recent summary of young cluster masses in the local group, to provide some context: http://arxiv.org/abs/1002.1961 Lithopsian (talk) 09:02, 9 June 2015 (UTC)