Astrophysicists discover how calcium formed in the first stars

An international team of researchers has explained for the first time the origin of calcium in early stars. Astrophysicists

It is believed that this element first appeared in the Universe during the slow boiling process in the hearts of early stars, and not as a result of supernova explosions.

Approximately 13.8 billion years ago, shortly afterAt the Big Bang, only the lightest elements, hydrogen, helium, and lithium, existed in the universe. Increasingly heavier chemical elements were formed later during nuclear processes in stars. In the new work, the researchers showed that in the process of nuclear fusion in the first stars (generation III stars), the heaviest element was calcium.

Previously, it was believed that the formation of calciumoccurred during powerful supernova explosions after the death of the first stars. Now astrophysicists have shown that this element can be formed already during the life of stars.

Our study describes for the first time how much of this calcium was produced: during the gentle boiling of burning hydrogen, rather than during a violent supernova explosion.

Alexander Heger, professor at Monash University's School of Physics and Astronomy

In 2014, Australian astronomers observedoldest star ever known to humans, a K-type red giant star SMSS0313-6708. Observations with space telescopes have shown that the composition of this star includes lithium, carbon, magnesium and calcium. However, the origin of calcium in the star remained a mystery.

The researchers conducted a series of experiments inChinese underground laboratory Jinping, which is located under the Sichuan Mountain at a depth of 2.4 km. The study showed that as soon as the combustion of hydrogen in the core of the star is completed, it continues in the shell. In this case, new stages of combustion begin inside the helium core. The experiments confirmed the hypothesis that calcium arises as a result of a key reaction of the breakthrough of the cycle of carbon, nitrogen and oxygen.

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