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WASHINGTON, Nov. 6: Astronomers have discovered what could be one of the oldest stars in the universe: a 13.5 billion-year-old body almost entirely made up of spit-out material of the Big Bang.
The discovery of the tiny star means there are probably more stars with a very low mbad and a very low metal content, perhaps even among the very first stars of the world. universe. "Thin Disk" – the part of the galaxy in which our own Sun resides.
The researchers stated that it was possible that our galactic neighborhood was at least 3 billion years older than previously expected.
"This star is perhaps one in 10 million. This tells us something very important about the first generations of stars, "said lead author Kevin Schlaufman, an badistant professor at Johns Hopkins University in the United States.
The first stars of the universe after the Big Bang would have been entirely composed of elements like hydrogen. , helium and small amounts of lithium.
These stars then produce heavier elements than helium in their nucleus and seed the universe when they explode as supernovae.
The next generation of stars formed from clouds of matter intertwined these metals, incorporating them into their composition. The metal content, or metallicity, of the stars of the universe increased as the cycle of birth and death of the stars continued.
On the other hand, most ultra-poor metal stars have orbits that take them across the galaxy and away from its plane.
The very weak metallicity of the recently discovered star indicates that in a cosmic genealogical tree it could only be a generation removed from the Big Bang.
Indeed, he is the new record holder of the star with the smallest complement of heavy elements – its content in heavy elements the planet Mercury.
On the other hand, our Sun has thousands of generations and a heavy element content equal to 14 Jupiters.
The star is part of a two-star system gravitating around a common point. By the late 1990s, researchers thought that only mbadive stars could be formed at the earliest stages of the universe – and that they could never be observed because they burn their fuel and die so quickly.
However, in the form of astronomical simulations. Having become more sophisticated, they began to suggest that, in certain situations, a star of that time with a particularly weak mbad could still exist, even more than 13 billion years after the Big Bang.
live for extremely long times. Red dwarf stars, for example, with a fraction of the mbad of the sun, would live up to billions of years.
The discovery of this new ultra-poor metal star, named 2MASS J18082002-5104378 B, opens the way opportunity to observe even older stars.
"If our inference is correct, low-mbad stars whose composition is exclusively the result of the Big Bang may exist," said Schlaufman.
"Even though we have not yet found an object like this in our galaxy, it may exist," he said. (AGENCIES)
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