jacobnavia wrote:
See ESO PR "The
onset of star formation 250 million years after the Big Bang"

https://www.eso.org/public/news/eso1815/

which also provides a link to the paper.

This press release refers to

Hashimoto et al,
"The onset of star formation 250 million years after the Big Bang"
https://arxiv.org/abs/1805.05966
(open-access)
published as
Nature 557, 392-395
https://www.nature.com/articles/s41586-018-0117-z
(paywalled)

This paper states

# We detect an emission line of doubly ionized oxygen at a redshift of
# 9.1096 +/- 0.0006, with an uncertainty of one standard deviation. This
# precisely determined redshift indicates that the red rest-frame optical
# colour arises from a dominant stellar component that formed about
# 250 million years after the Big Bang, corresponding to a redshift of
# about 15.

That's z=17. Looks nice z=17, with now an incredible bright QSO (quasar)
with 20 Billion (!) solar masses and so bright that its light arrives
directly to us, no gravitational lensing required, imagine. It is the
most brilliant object detected so far by humans.

On the contrary, Hashimoto et al are observing a gravitationally lensed
galaxy (the lensing increases it's apparent brightness by about a factor
of 10, they say), not a QSO. They observe the galaxy at redshift z=9.1,
and they infer from the galaxy's color that it contains stars which
formed at a redshift of about z=15.

https://arxiv.org/pdf/1805.04317.pdf

*This* paper (1805.04317) describes an object at redshift z=4.75, not
redshift z=17. (The paper does refer to "z=17", but that's a *magnitude*
(log of brightness in a certain wavelength range), not a redshift. You
can tell this because the paper says "magnitude z=17".)

The star mentioned above has oxygen, what implies at least several
generations of stars to produce it, and then exploding and dispersing
the oxygen into space so that it slowly condenses into anew stars...

As Phillip Helbig noted elsewhere in this thread, the first generation
of stars could certainly have synthesized oxygen. See, for example
https://en.wikipedia.org/wiki/CNO_cycle
https://en.wikipedia.org/wiki/Alpha_process
(The first figure in
https://en.wikipedia.org/wiki/Nucleosynthesis
shows "Exploding massive stars" as the main origin of oxygen; offhand
I'm not sure if that's correct. Certainly non-explosive nucleosynthesis
can also yield oxygen.

[Moderator's note: Presumably what is important is not which stars
produce the most oxygen, but which stars deposit the most oxygen into
the interstellar medium from which new stars form. If the star doesn't
explode, most of the oxygen won't get out. -P.H.]

--
-- "Jonathan Thornburg [remove -animal to reply]"
Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
currently visiting Max-Plack-Institute fuer Gravitationsphysik
(Albert-Einstein-Institut), Potsdam-Golm, Germany
"There was of course no way of knowing whether you were being watched
at any given moment. How often, or on what system, the Thought Police
plugged in on any individual wire was guesswork. It was even conceivable
that they watched everybody all the time." -- George Orwell, "1984"