Talk:Metallicity

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[edit] Corrected a statement

"regular chemistry has almost no relevance in astrophysics. This is patently false - I believe it was meant to read "regular chemistry has not relevance in a discussion of stellar interiors. I changed it as such. —Preceding unsigned comment added by 160.39.157.91 (talk) 23:12, 1 May 2008 (UTC)


[edit] Biggest star that can form today

"The most massive star that can form today is about 110 solar masses with a possible extreme maximum upper limit of 150 solar masses" i.e. "The maximum mass for a star today is 110 solar masses, with a maximum mass of 150 solar masses". Which is it? 110 or 150? Or is it that 110 is the largest mass that a star can start with, and 150 is the largest mass that a star can have and still be stable after accretion etc? AstroDave (talk) 10:50, 14 April 2008 (UTC)

[edit] Merger from Stellar population

I see that Stellar population has been merged into this article. This seems a bit odd to me - while metalicity is a big part of the population classes, the population classes also have other aspects with stellar and galaxy formation, and as such I think that they deserve to be in their own article. Mike Peel 18:16, 22 November 2006 (UTC)

Perhaps that is the case, but there was nothing in that article that was not in the reconstituted Metallicity article. If there are other factors which inlfluence stellar classification, then perhaps they could be added to a newer version of the article, but the article, as written, was only a shorter version of this one. Serendipodous 18:51, 22 November 2006 (UTC)
Fair enough. I'd like to see them split back at some point, but for now I guess they're OK being combined. Mike Peel 19:27, 22 November 2006 (UTC)

[edit] Population 0 stars

Population 0 stars redirects here but I can't find any information about them in any of the five articles I combined to create this one, nor can I find any information on them in Google or Google Scholar. I even went back and checked every past edit in Stellar population, to which the redirect linked originally, but found no mention of them. Does anyone know what they are? Serendipodous 16:59, 25 November 2006 (UTC)

Never heard of it – maybe confused by luminosity class 0?? As much as I can understand, they represent a far future luminosity class. Rursus 17:29, 8 January 2007 (UTC)
Now the really bad qualities of Wikipedia occurs – there really are hits on "population 0 stars". All of them obviously being information copied from wikipedia! No real information, but as soon as desinformation occurs on wikipeda, it propagates over Internet. This is neither a conventional responsibility issue, nor a honesty issue - this is a mathematical complexity issue: imagine a situation when desinformation overweights the true information (YES, there is a truth, and there is an objectivity – otherwise my involvement here is meaningless) then desinformation will propagate over internet despite being removed from wikipedia, if desinformation propagates more than true information, the meaning of Internet will be truly destroyed. (Conclusion: I will delete "population 0 stars". Rursus 19:12, 8 January 2007 (UTC)
As another explanation, perhaps someone confused the term with a class 0 protostar? Sadly, I see that there's no reference of classes on the protostar page, so I guess that's something else to go on the to do list... Spiral Wave 17:26, 27 January 2007 (UTC)
Uh, turns out the class descriptions are tucked away in the Herbig-Haro objects article. Seems to me a short description should go in the protostars article too - a more 'obvious' place to look - but duplicating material seems a waste (and it's too good to remove from the featured article). Unless anyone has any thoughts, I'll just leave it then... Spiral Wave 00:02, 28 January 2007 (UTC)

[edit] More needed

Ordinary school books (university level) tells us more – mostly about subpopulations betw popI and popII. More is also needed for my carbon stars extras to make sense. L8R Rursus 17:27, 8 January 2007 (UTC)

Done (L8R) Rursus 00:27, 9 January 2007 (UTC)

[edit] article missed out a candidate Pop III HII galaxy.

Might I comment that the article has left out the possible detection of a Pop III starburst at z~3.

http://news.bbc.co.uk/2/hi/science/nature/3227221.stm (the BBC's summary of the work).

As Fosbury et al. (2003 ApJ 596 797) explain, the spectrum of this HII galaxy are difficult to explain in terms of photoionization by a 'normal' starburst - very hot stars (~80,000 K) seem to be required. 132.248.1.196 00:02, 18 January 2007 (UTC)

Then include it. This is Wikipedia. Serendipodous 11:13, 18 January 2007 (UTC)
The article is intriguing indeed, but it does not mentions population III, it mentions that a Lynx arc is a structure with early super-luminous stars nearest to what we believe the "earliest stars" to be – we believe that means pop III, but that's not what's observed in the Lynx arc. The article is vaguely relevant – but maybe not enough so ??? Rursus 22:08, 28 January 2007 (UTC)
I'm inclined to agree with Rursus - the article is 3 years old, if there was any further suspicion here I expect we'd have heard of it by now. If anyone knows of any such newer research on this nursery, that might well be worthy, but I think this by itself is too vague. We'll probably have to wait until the James Webb is launched before we get any real observations. Spiral Wave 00:06, 29 January 2007 (UTC)

[edit] Contradiction

The intro says Pop I was created first, then Pop II, then Pop III, to which the sun belongs. Later the text says the sun is Pop I, and the oldest are Pop. III. I don't know which is right, just that they contradict. UnitedStatesian 03:09, 31 March 2007 (UTC)

Thank you, I have fixed this. (Pop III stars came first.) Spiral Wave 07:37, 31 March 2007 (UTC)

[edit] Deblippification

I removed lot's of ":s and some ":s. F.ex. "Big Bang" is replaced with Big Bang because it's an established term. "Heavy" is not "heavy" but in real life heavy. When highlighting a newly introduced term I use to use gizmo (bold), at other emphasis I prefer italic is a necessity. Blips should be preferred when citing in running text, or just using a simile, like: he "exploded" from rage (not me, not now, be calm!) Rursus 17:07, 1 April 2007 (UTC)

[edit] Units of metallicity

I keep running across the unit of "dex" for metallicity, which seems to be for [Fe/H]. However, I haven't seen an explanation/derivative of this, and am having a fair few problems finding one. Does anyone know more about this, and if so could they post it either here or on the article, please? Thanks Mike Peel 07:42, 19 April 2007 (UTC)

It's one of those irritating things that it's always assumed you already know about. As such, I don't know of any papers explaining it; but this Caltech page explains the units, and this page from North Carolina explains the etymology: it's a (now-deprecated) contraction of decimal exponent. Spiral Wave 17:23, 20 April 2007 (UTC)

[edit] How do they get these figures?

"The number of iron and hydrogen atoms per unit of volume respectively" are stated as requirements for the metallicity equation yet the entry makes no mention of how these measures are actually detected (for our own star and others). MatthewKarlsen 17:53, 25 May 2007 (UTC)

I believe that with a Spectrometer —Preceding unsigned comment added by 86.122.202.153 (talk) 20:44, 1 January 2008 (UTC)

[edit] How could Population III stars create the first 26 elements if they contained no metals?

About half of the first 26 elements are metals, so how could they create these metals via nuclear fusion without containing them? —Preceding unsigned comment added by 72.65.160.182 (talk) 08:44, 7 March 2008 (UTC)

After the elements were fused within the star, the star then contained metals. But the terms metal-rich or metal-poor (or metal-less) generally refer to stars early in their lives when they are fusing Hydrogen to Helium and the heavy metals that were left over from previous stars can be identified. 24.117.155.195 (talk) 03:51, 12 March 2008 (UTC)