2024-03-22 15:53:42
The Gaia space telescope, dedicated to mapping the Milky Way, has identified two groups of primitive stars in the heart of our galaxy, which are the origin of its formation more than 12 billion years ago, according to a recent study.
With their regular rotational motion, these two “stellar streams,” each with a mass equal to 10 million suns, are like the “first building blocks” of the ancient core of the Milky Way, where the first stars formed before the galaxy grew into its current spiral shape, Khayati Malhan said. From the Max Planck Institute for Astrophysics in Germany to AFP.
The main author of the study, the results of which were published in the Astrophysical Journal, explained that “this is the first time that we have been able to identify parts of this proto-galaxy,” which was named Shakti and Shiva, after two Hindu gods, “whose union led to the emergence of the universe.”
The European Space Agency’s Gaia probe, which has been operating 1.5 million kilometers from Earth for 10 years, delivered a 3D map in 2022 of the locations and movements of more than 1.8 billion stars.
This map made it possible to identify a group of stars nicknamed “Poor Old Hearts” due to their old age, due to their weak metallic composition (a chemical indicator of the star’s age), and their central location.
This was an important step for Hungarian archaeology, which aims to reconstruct different eras of the Milky Way’s history “in the same way that archaeologists reconstruct the history of a city,” the Max Planck Institute explained in a statement.
Thus, the model of the Milky Way’s evolution simulates “an ancient central city surrounded by newer regions,” according to the institute.
But “the further we go back in time and space, the blurrier the picture of galactic history becomes,” says Khayati Malhan.
So astronomers investigated this ancient nucleus, which they identified in 2022. They took a sample of 6 million stars, and studied their chemistry and location using, in particular, artificial intelligence.
Thus, they put their fingers on two “stellar streams”, Shakti and Shiva, which formed between 12 and 13 billion years ago, in the early ages of the Milky Way.
Surprisingly, their stars have abnormally high metallicities for stars of this age. This is a possible sign that she comes from an earlier generation of stars. When she died, she released chemical elements that “seeded” the interstellar gas from which the stars Shakti and Shiva were formed.
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