The newly launched James Webb Space Telescope is expected to allow astronomers to explore the distant regions of the universe in search of its oldest stars. But the discovery by an international team could save them from having to search just yet. Researchers have just got their hands on stars with a very low – and therefore very old – metallic content there, on the outskirts of the Milky Way.
for us Soleil It definitely consists of more than 98% ofhydrogen And’helium. the lightest chemical elements From’being. But it also contains some heavier elements. These heavy items – like Carbon, toOxygen where is the Act, generally referred to as metal -, the sun takes them from Gas Who condenses it. Heavy items scattered there stars huge at the end of their lives. Generations of stars predated our sun. Hence measure what Astronomy scientists call her mineral The star gives an idea of his age. The more metal, the smaller the star.
However, an international team led by A Researcher at the Strasbourg Astronomical Observatory (CNRS) has just been updated, in the heart of Milky WayA group of stars whose metallicity appears to be very low. About 2500 times weaker than our sun. And much less than those measured in other structures elsewhere in the universe.
In fact, this group of stars is not quite in our heart galaxy. Even on the side of its surroundings. on the south side. And these stars travel on a orbiting which range from 20,000 to 90,000 light years from the middle Milky Way. Although this stellar stream, which the researchers named C-19, is about 30 times as wide full moonIt is invisible in our sky whenEye Not.
Rewrite the history of the formation of stars and galaxies?
His discovery shakes up the current models of star formation, Dr’Clusters and galaxies. Because until then, astronomers had not even thought about the possibility of such structures, consisting only of stars with a low metallic content. At best, imagine that they would all have gone away from our universe. C – 19, and its stars with a mineral content of less than 0.05% of the Sun, on the contrary, the first constituent elements of the Milky Way formed in mineral-poor environments.
It’s thanks to mission data Jaya That astronomers got their hands on C-19. By applying an algorithm on them to discover the flow of stars. Pristine’s program, which aims to expel low-metal stars in and around the Milky Way, has revealed its astonishing properties. And other observations, including high spectra Precision, confirmed that C-19 was the remains of A spherical mass A group of several thousand to several million stars formed at the same time and whose metallicity is generally between 1 and 10% of the torn sun.
While astronomers used to study distant galaxies to get close to some ancient stars – due to the time it takes for their light to reach Earth – they can now consider studying ancient structures as well. But closer to us. A little as if it was a new one Window It just opened into the first sequences of star formation in our universe.
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