Methusalah's star

I'm composing a mail for His CeilingCatness at WEIT, but it needs work.

So far : 

A common attack tactic for creationists is general assault on science - which they frequently support by deliberate mis-reading of reports, and/ or mixing of data from different eras. As you well know.

A popular target is that in the mid-late 1970s some stars had their ages estimated up in the 10+Ga (giga-annum, billion years ago) age range, while measurements from the ground put the cosmic microwave background at around 6 to 7 billion years. Obvious fodder for the god-squaddies. "Science can't be right, therefore God!"

This factoid sometimes gets described as the "Methuselah Star" and variations thereof.

One of the particular stars involved, and the most extreme example is in the Henry Draper star catalogue https://en.wikipedia.org/wiki/Henry_Draper_Catalogue, number HD 140283 (catalogue data and references at http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+140283&submit=SIMBAD+search). This is a spectroscopic catalogue that was published 1918-1924. 19-teens era spectroscopy required relatively bright stars, and it should be no surprise that "Methusalah's Star" is quite close (parallax 16.1140+/-0.0720 milliarcseconds (from SIMBAD, link above) - translating to 62+/-0.1 parsecs, 202.4+/-0.3 light years. That's about the total thickness of the Milky Way's "disc" ; the Milky Way has a shape similar to a CD or DVD disc. Really quite close! Corollary : in the rest of the galaxy, there are probably a lot of equally old, if not older, stars.

Multiple measurements since the 70s have improved our estimate of the age of the universe (BOOMerang https://en.wikipedia.org/wiki/BOOMERanG_experiment, WMAP https://en.wikipedia.org/wiki/WMAP Planck, https://en.wikipedia.org/wiki/Planck_Surveyor), and converged on 13.772±0.040 Ga as the age of the CMB - which is about 370,000 years after the big bang ( 0.00037 Ga - compare with the uncertainty cited above). Obviously that no longer conflicts with the age estimate for "Methusalah's Star".

Having updated the age of the universe, and the distance to the "Methusalah Star", what about it's age? Well that has been updated too. (Arxiv link below) Unfortunately, stars don't come with "Best Before" dates, or even interesting sets of isotopes (which we can read at many trillions of km range), so estimating their ages is rather difficult. But that has improved even more since the 1970s then the age estimates for the CMB.

What initially attracted attention to HD 140283 - why indeed, the astronomers producing the catalogue considered it worth taking note of - is that it's spectrum contained very few, weak absorption lines for what the astrophysicists call "metals" (their jape is that anything which is not hydrogen or helium is a "metal" ; hilarious!). In the 19-teens that was just a datum. As the characterisation goes, astrophysics at that time was more "stamp collecting" than "science". However when Hoyle (and others) developed a theory of powering stars by nucleosynthesis in the 1930s and 40s, this both justified the value of "stamp collecting science" and provided a tool for understanding the ages of stars.

[explain stellar age modelling]

Need to keep the emphasis on nucleosynthesis and core heat production, not get side-lined into primordial elements.