2020-01-24T12: 09 + 0300
2020-01-24T12: 58 + 0300
https://ria.ru/20200124/1563819386.html
Scientists have discovered unusually much oxygen in the atmosphere of an ancient star
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RIA News
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RIA News
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Oxygen is the third most abundant element in the Universe after hydrogen and helium and the main element of the earth’s crust. This is the chemical basis of life on Earth, it is necessary for breathing and is part of the molecules of which all organisms are built.
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There was no oxygen in the early Universe – it was formed as a result of nuclear reactions taking place deep in the bowels of massive stars (10 times the mass of the sun).
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Studying the history of the appearance of oxygen and other elements of the early Universe requires observation of the most ancient, or, as astronomers say, “primitive” stars located on the far outskirts of our Galaxy, in the so-called galactic halo.
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An international team of astronomers from the University of California at San Diego (USA), the Institute of Astrophysics of the Canary Islands (Spain) and the University of Cambridge (UK) studied the atmosphere of one of the oldest and poorest elements of “primitive” stars – J0815 + 4729, which is located in more less than five thousand light-years from us in the direction of the constellation Lynx.
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The HIRES high-resolution echelle spectrometer at the Keck Observatory in Hawaii helped to make the discovery. A five-hour observation allowed scientists to measure the content of 16 elements in the atmosphere of a star.
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“Stars like J0815 + 4729 are called halo stars,” the words of one of the authors of the study, the astrophysicist of the University of California, Adam Burgasser, are quoted in the press release of the observatory. “This is due to their approximately spherical distribution around the Milky Way, unlike flat disk of younger stars, including the Sun. “
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“The primitive composition of the star indicates that it formed during the first hundreds of millions of years after the Big Bang, possibly from the material of the first supernovae of the Milky Way,” adds Jonay González Hernández, lead author of the study at the Canary Institute of Astrophysics.
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HIRES data showed a very unusual chemical composition of the star’s atmosphere. It has a lot of carbon, nitrogen and oxygen – respectively 10, 8 and 3 percent of the amount of these elements on the Sun. But the remaining elements, including calcium and iron, are very few – only about one millionth of the solar values.
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So far, astronomers know only a few as ancient stars as J0815 + 4729. All of them are located in the halo of the Milky Way, but none have the same huge reserves of carbon, nitrogen and oxygen in comparison with the iron content.
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The results of the study indicate that oxygen and other important elements are formed in the Universe as a result of supernova explosions of the first generations of stars.
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“Thirty years ago, we began to study the presence of oxygen in the oldest stars in our galaxy. Preliminary results already indicated that this element was produced in large quantities in the first generations of supernovae. However, we could not even imagine that we would find such an impressive example of enrichment oxygen like that of this star, “said Rafael Rebolo, director of the Canary Islands Institute of Astrophysics.
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