Researchers have studied the processes that could accompany the formation of globular clusters, one of the oldest objects in the universe. The results of the study help to better understand how the first generations of stars were formed and how the chemical composition of matter in young galaxies changed.

Globular clusters are dense systems containing hundreds of thousands and even millions of stars. Many of them originated more than 10 billion years ago, so scientists consider such objects as peculiar witnesses of the early history of the universe.

The scientific work compared the properties of globular clusters observed in the modern Universe and near-galactic gas clouds that existed at different stages of cosmic evolution. Special attention was paid to metallicity, the content of chemical elements heavier than hydrogen and helium in a substance.

For astronomers, metallicity is an important indicator of the age and history of matter. Immediately after the Big Bang, heavy elements practically did not exist. They gradually accumulated due to the stars, which synthesized new chemical elements and ejected them into the surrounding space after completing their evolution.

The analysis showed that the metallicity distributions of globular clusters and near-galactic clouds have a similar structure. In both cases, the scientists found several characteristic stages of chemical enrichment of the substance. Associate Professor, Ph.D., Head of the Department of Space Physics Irina Acharova told:

"The statistics of the metallicity distribution of near-galactic clouds and globular clusters clearly indicate that for every 3 million solar masses of stars, there was a cloud mass of 100 million solar masses. Thus, it is concluded that star formation is effective in the early stages of evolution."

By observing distant near-galactic clouds, astronomers are simultaneously looking into the past. Light from the most distant objects has been traveling to Earth for billions of years, so modern telescopes allow us to see the universe as it was long before the appearance of the Solar system.

Based on these data, the researchers considered a scenario according to which large gas clouds could successively undergo several stages of accumulation of heavy elements. At each of these stages, new globular clusters could form in the clouds, after which the chemical composition of matter continued to change under the influence of subsequent generations of stars.

In addition, the authors assessed how the properties of stars could depend on the chemical composition of the medium in which they were formed. Estimates of the maximum mass of stars capable of completing their evolution with a supernova explosion were obtained for various stages of chemical enrichment of matter.

The research can be useful in interpreting data from modern ground-based and space-based observatories. Today, astronomers are receiving more and more information about distant galaxies in the early universe, and such models help to understand what processes took place in them billions of years ago.

"The developed methodology for analyzing the properties of globular clusters and near-galactic clouds in the modern era makes it possible to clarify the processes occurring at the initial stages of galaxy formation," noted Irina Acharova.

The results obtained help to better understand the processes of star formation in the early universe and the history of the formation of the oldest star systems. According to the researchers, studying globular clusters makes it possible to reconstruct events that took place billions of years ago, when the first generations of stars and galaxies were forming.

If the early universe had not learned how to efficiently produce and distribute heavy elements, rocky planets like Earth would never have appeared in it. It is also a search for an answer to the question of the origin of the substance that we ourselves are made of. All the iron atoms in our blood, the calcium in our bones, and the oxygen we breathe were once created inside stars. Therefore, studies of the first generations of stars help to understand why the modern universe looks this way.