For the first time, scientists have been able to explain the secret of an unusual chemical composition in one of the most distant galaxies in the universe. A state-of-the-art theoretical model created by groundbreaking research may hold the key to better understanding the distant universe. Professor Chiaki Kobayashi from the Center for Astrophysics Research (CAR) at the University of Hertfordshire led the groundbreaking research using data from the James Webb Space Telescope (JWST).

The name of the galaxy that Professor Kobayashi studied GN-z11 – It “takes place” only 440 million years after the Big Bang. But spectra obtained by JWST showed unusually high nitrogen content in GN-z11, surprising many scientists. While only light elements were formed during the Big Bang, when the stars died at the end of 13.8 billion years of cosmic time, carbon and heavier elements formed in the stars and dispersed in the interstellar medium.

One of the hypotheses put forward so far to explain the presence of so much nitrogen in the galaxy was that the element could be produced by a supermassive star that is 50,000 to 100,000 times more massive than our Sun. But Professor Kobayashi’s research not only refuted this hypothesis about supermassive stars and possibly the remaining supermassive black hole. Instead, it created a new way to understand early galaxies.

Professor Chiaki Kobayashi, professor of astrophysics at the University of Hertfordshire, said: “The galaxy tells us not about an unusual star, but about an unusual episode of galactic life. We found that early galaxies had an ‘explosive’ star formation that caused this unusual chemical composition”.

“For only a short period of time, estimated in our model to be about a million years, nitrogen is much more abundant than oxygen.

“Our theoretical model, which does not require any special enrichment sources as in ordinary stars such as our galaxy, also predicts the abundance of all elements that we cannot detect even with the best telescope we currently have.”

Professor Kobaisakhi, who also studies nuclear astrophysics, explains that the theoretical model of an exploding star helps expand our understanding of the early universe.

“In our model, the galaxy undergoes intermittent, vigorous star formation, and fairly massive dying stars called Wolf-Rayet stars produce this particular element, nitrogen, before the major heavy elements, such as oxygen, are produced by supernovae.”

“What we believe, and what is of great interest to all who study our universe, is that this pattern testifies to an extremely dramatic phase of galaxy evolution.”

Addressing the future and what this discovery means for astrophysics, Professor Kobayashi added: “We would like to see many other galaxies with unusual chemical compositions like this.”

“We would also like to see more elements besides nitrogen and oxygen in these galaxies. Because different elements are produced from different types of stars on different time scales, elemental abundance patterns provide a fossil record for understanding the history of the universe. I call this the ‘Extragalactic Archaeology’ approach.”