The first stars of Universe were born in groups and not individually, an international team of scientists found after research conducted using artificial intelligence. After the Big Bang, the only elements in the Universe were hydrogen, helium and lithium. Most of the other elements that make up the world around us were produced by nuclear reactions in stars. Some elements are formed by nuclear fusion in the core of a star and others are formed in the explosive death of a star. The first generation of stars, the first to produce elements heavier than lithium, are of particular interest but difficult to study because none have ever been directly observed and all are thought to have already exploded as supernovae. Researchers try to draw conclusions about first-generation stars by studying the chemical “signature” of the first generation of supernovae that was imprinted on the next generation of stars. Based on their composition, extremely metal-poor stars (rare but numerous enough to be analyzed as a group) are thought to be stars that formed after the first round of supernovae.

In the research, published yesterday in The Astrophysical Journal, a team of scientists from the University of Tokyo, the National Astronomical Observatory of Japan and the University of Hertfordshire used a new approach using artificial intelligence to interpret the chemical composition in more of 450 extremely metal-poor stars observed with telescopes. They found that 68% of these stars have a chemical signature consistent with enrichment from multiple previous supernovae. In order for the remnants of several previous supernovae to have been mixed into a single star, it is inferred that the supernovae must have occurred in close proximity, and thus in many cases the first-generation stars must have formed together in clusters.

The research team hopes to apply this method to new data from current and planned observational surveys to better understand the early days of the Universe.