James Webb Space Telescope observes primordial stars creating extreme nitrogen in ancient galaxies

The James Webb Space Telescope has observed chemical signatures in distant galaxies that provide evidence for the existence of supermassive primordial stars, also known as Population III stars, in the early Universe.

Researchers identified extreme nitrogen enrichment in the galaxy GS 3073, a phenomenon that ordinary stars cannot produce.

The findings indicate that stars with masses ranging from 1,000 to 10,000 times that of the Sun existed approximately 300 million years after the Big Bang.

These stars likely contributed to the formation of supermassive black holes in early galaxies, according to a research team led by Devesh Nandal from the University of Virginia and the Harvard-Smithsonian Center for Astrophysics (via Universe Today).

Detection of extreme nitrogen in GS 3073

The research team, which included Daniel Whalen from the University of Portsmouth, Muhammad A. Latif from the United Arab Emirates University, and Alexander Heger from Monash University, utilized JWST to analyze the spectra of the galaxy GS 3073.

The readings revealed a nitrogen-to-oxygen ratio of 0.46, which is much greater than that produced via normal stellar processes.

The high nitrogen content agrees with the predicted conditions for very massive Population III stars.

GS 3073 houses an actively feeding black hole at its center, thus implying a possible link between the nitrogen enrichment and the remains of primordial supermassive stars.

Moreover, the analysis suggests that the nitrogen signature is confined to the central area of the galaxy, which reinforces the argument that it originated from massive stars rather than being dispersed through galactic processes.

Mechanism for nitrogen production

According to the team’s models, these supermassive stars produce nitrogen through helium fusion in their cores.

Carbon formed during this process is transported to hydrogen-burning regions via convection. In these regions, carbon reacts with hydrogen to produce nitrogen.

The nitrogen is then dispersed into the surrounding interstellar medium over the star’s lifespan, which lasts millions of years.

The models also suggest that these stars do not explode as supernovae but collapse directly into black holes.

This process would account for the nitrogen-to-oxygen ratio observed in GS 3073. It could explain the origin of supermassive black holes observed in early galaxies, as reported by Universe Today.

Implications for early universe studies

The detection of nitrogen in GS 3073 advances our understanding of the chemical evolution of galaxies between 380,000 and 1 billion years after the Big Bang, a phase known as the Cosmic Dark Ages.

With JWST imaging, the light from this period was previously considered too dim for even the newest instruments to capture.

These results provide scholars with a means of tracing the evolution of Population III stars and their subsequent mixing in primordial galaxies.

Further surveying of JWST is expected to confirm the presence of more galaxies with corresponding nitrogen signatures, allowing for even deeper probing of the supermassive primordial stars and their impact on galaxy formation, as noted by Daniel Whalen and his colleagues.

Models, together with observations, suggest that supermassive Population III stars existed for a short time only and left behind detectable chemical signatures.

Most probably, these stars collapsed directly into black holes, which can explain why supermassive black holes already existed less than a billion years after the Big Bang.

The nitrogen signature detected in GS 3073 narrows down the consideration to stars of up to 10,000 solar masses, thus restricting the characteristics of the early stellar populations quite tightly.

Stay tuned for more updates.