Population III stars were fusing hydrogen before it was the hot thing to do

featured image credit: M. Kornmesser/European Southern Observatory

Sobral et al. in recent work slated for publication in The Astrophysical Journal, claim observation of a galaxy, CR7, likely hosting a large contingent of Population III stars. The New York Times also has good summary; you know it’s important when actual stars get the movie star treatment. While I’m not in a position to evaluate the potential gotchas of the observations (Sean Carroll succinctly put it recently, “Specialization is real, folks!”–even for self proclaimed polymaths), I will say if confirmed these observations are super exciting for understanding the lives of the earliest stars and perhaps even how the first supermassive black holes formed. Soooo looking forward to JWST!

Now why is the observation of some galaxy so exciting (besides the fact that the name was purportedly “inspired by [a] great Portuguese soccer player”)? Isn’t observing galaxies what astronomers do for a midnight snack? Well… Population III stars haven’t been observed before and Sobral et al. conclude the most likely explanation of the properties of the CR7 galaxy  implies it is “the strongest candidate for [hosting a] PopIII-like stellar population found so far”. Population III stars are the earliest stars, composed of primarily hydrogen and helium.  Due to being first on the whole Universe scene (Population III stars were fusing hydrogen before it was the hot thing to do) Population III stars would be born in a different environment with the aforementioned unique material composition, and  thus behave and evolve differently than the regular Population II and Population I stars we have observed (Pop II/I are hipster stars hopped up on heavier metals, derivative of exploded Population III stars, basking in the glow of their predecessors).

And how so? Most saliently, Population III stars would be comparatively more massive with a motto “live fast, die young” joining the stellar equivalent of the 27 club, quickly giving way to the next generation.  Thus, while on strong theoretical grounds, Pop III stars have been difficult to observe directly due to the fact their existence was so long ago coupled with their short life expectancies.

We’ll see what surprises the Universe has in store thanks to the work of pioneering astronomers like Sobral et al. pushing the boundaries of telescope technology to observe pioneering stars.

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