Did the models claim 400 million years was too early for formation?
Yes, that's very likely, but future observations (e.g. JWST) will improve the unwanted degrees of wiggle. Part of the problem is trying to understand how having only hydrogen and a little helium would form a star, how big they could be, etc. These stars don't exist even in the old globular clusters.
I suspect all is in order, but we still need observations to help build better models.
That's sounds logical. The objective evidence available to tweak that early period is very scant, though the overall age does come with strong evidence.
The article seems to strongly discount the 500M to 1B yr period for early formation. These stars and galaxies, regardless of their formation period, must exist to explain today's stars and galaxies, reionization, etc., so it's just a matter of time before equipment and techniques get us to where we need to be.
Yes, but even these are likely not considered in the Pop III class. There were no metals for the first stars since Li and Be were so rare.
Those clusters consists of very old stars, but only the less massive stars survive for very long periods, and smaller stars are more convective so as they produce heavier elements. These, I assume, would rise to the surface, and their spectrum will reveal their greater metallicity.
IIRC, the Sloan Survey used fiber optics that ran through metal templates to align perhaps a few hundred stars for each imaging section to get the spectrum of each star. The Hobby-Eberly a year or so ago was taking time to do something similar but on a larger scale with its 9 meter mirror, and all for spectroscopy.
Good question. It's my understanding that these clusters are still enigmatic as to how they are what they are.
Outside of the globular cluster regions that are normally outside the galactic plane, it might take a rogue intergalactic star to remain unaffected by the spewing of normal stars, novae, and supernovae. But it would suffer with growing metalicity over time and, being small, the convective issue as mentioned above.
What is the BBN? Is this the same as the BBT (Big Bang Theory)?
Given that Pop II stars require metals that were produced by Pop III stars, and that the BBT has only H and He (9 to 1 number ratio) as the only atoms to form (Li & Be were very low in number), then I am puzzled by what you mean.
It's the other 20 or so lines of evidence that have produced an overwhelming confluence of validity for the theory, hence it is fair to assume the Pop III discoveries are inevitable once we can see more (better scopes). This is similar to planet formation theory that "suffers" due to the fact that most exoplanets are large (contrary to the models). But this was expected since the small ones are much harder to detect.
But I take this in the context that only more recently have models surfaced to explain how massive Pop III could form, so early compositional models had to struggle, I expect. This is still new and exciting territory.
This was about 6 years before Hoyle introduced our more modern understanding thanks to his brilliant work on C12 resonance.
Agreed, but the current BBN isn’t about metal production.
Right, it would be very disruptive if Pop III stars are not found, eventually. The 1948 view has been refuted with things like the Lyman-Alpha Forest.
Yes, but there are many times I have to separate kind from degree. The metals are there but, apparently, to the degree expected.
How could H and He "evolve" into the post Pop III levels of metallicity, which then gave us the Pop II stars, The fusion temperatures necessary require some of these very massive stars, so if we can eventually see to a time just after atoms formed (Reionization) and no Pop III are found, then a very big challenge will be on the table.
Yep.Searches continue, still MIA apparently
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