James Webb Space Telescope makes 1st detection of diamond-like carbon dust in the universe's earliest stars

A very interesting report and the reference provided, 33-page PDF to study. Perhaps there never was pristine, metal free gas in the Universe and JWST is finding this, lack of evidence for the metal free gas during BBN and the cosmic dark ages in the BB model. IMO, that would suggest problems in the 4 stages of the cosmic fireball evolution (heavy particle, light particle, radiation era, matter era) developed to explain the presence and origin of the CMBR in the BB model.

The abstract states - “Large dust reservoirs (up to ~10^8 M⊙) have been detected in galaxies out to redshift z ∼ 8, when the age of the universe was only about 600 Myr. Generating significant amounts of dust within such a short timescale has proven challenging for theories of dust formation and has prompted the revision of the modelling of potential sites of dust production such as the atmospheres of asymptotic giant branch (AGB) stars in low-metallicity environments, supernovae (SNe) ejecta, and the accelerated growth of grains in the interstellar medium (ISM). However, degeneracies between different evolutionary pathways remain when the total dust mass of galaxies is the only available observable. Here we report observations of the 2175 Å dust attenuation feature, well known in the Milky Way (MW) and galaxies at z ≲ 3, in the near-infrared spectra of galaxies up to z ∼ 7, corresponding to the first billion years of cosmic time. The relatively short timescale implied for the formation of carbonaceous grains giving rise to this feature suggests a rapid production process, likely in Wolf-Rayet (WR) stars or SN ejecta.”

There is some recent discussion on the absence of pristine gas observations on the forums too.

Here is another report on this very interesting topic.

Webb sees carbon-rich dust grains in the first billion years of cosmic time, https://phys.org/news/2023-07-webb-carbon-rich-grains-billion-years.html

Phys.org reported, "Models have previously suggested that nano-diamonds could be formed in the material ejected from supernovas; and huge, hot Wolf-Rayet stars, which live fast and die young, would give enough time for generations of stars to have been born, lived, and died, to distribute carbon-rich grains into the surrounding cosmic dust in under a billion years. However, it is still a challenge to fully explain these results with the existing understanding of the early formation of cosmic dust. These results will go on to inform the development of improved models and future observations…"

Ref - Carbonaceous dust grains seen in the first billion years of cosmic time, https://www.nature.com/articles/s41586-023-06413-w, 19-July-2023. “Abstract Large dust reservoirs (up to ~10^8 M⊙) have been detected *ref* 1-3 in galaxies out to redshift z ∼ 8, when the age of the universe was only about 600 Myr. .."

My note. Using Kempner cosmology calculator, https://www.kempner.net/cosmic.php, H0=67.04 km/s/Mpc, z=8.0, age of universe at z = 0.638023 Gyr, look back time to z = 13.1919 Gyr. The angular diameter distance maps to 1 arcsecond scale where 1” = 4.926355 kpc. The comoving radial distance = 9145.2 Mpc or 2.9827653E+10 light-years away from Earth today. Using H0 = 67.04 km/s/Mpc, space is expanding 2.0438269E+00 c or slightly faster than 2x speed of light.

Besides explaining the presence of carbon dust seen in early galaxies via some accelerated r-process or s-process mechanisms, the cosmology calculators pop up other interesting features too when using various z values (redshift numbers) reported in the observations.