Before death, a cloud of material forms around the star.
A team of astronomers announced that they had found a way which can be used to predict the quick death of a star. According to researchers, the appearance of a thin shell of material around the red giant indicates that it may soon explode, reports Space.com.
As a powerful star approaches the end of its life, it goes through several stages. The core goes from the synthesis of hydrogen to the synthesis of heavier elements, at the end of this process iron is formed in the core. Because this element depletes energy rather than releasing it, it results in the death of the star. As a result, it “turns inside out” in a spectacular explosion called a supernova.
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But despite the fact that such radical processes take place in the depths, from the outside it is difficult to tell that something is happening. It is clear that near the end of life, such stars increase in size and also become extremely bright.
The most vivid example of such a star is Betelgeuse. If this luminary could be placed at the center of the solar system, it would occupy all the space up to the orbit of Jupiter. Betelgeuse could explode as a supernova at any moment. But in astronomical terms, “any moment” can last millions of years. And it was impossible to predict the supernova explosion more precisely.
Now scientists have said that a supernova explosion can be predicted several years in advance. To do this, they studied several supernovae of the rare type II-P. Unlike other supernovae, these explosions remain bright long after the initial burst.
In several catalogs, scientists have found images of the stars before they exploded, all of which at the time were red giants similar to Betelgeuse. . This is an obvious sign that such stars remain the main contenders for a supernova explosion.
It is believed that stars that go through such explosions are first covered with a thin shell of material. Such a veil is much denser than the one surrounding Betelgeuse at the moment. It is due to the heating of this material by a shock wave that the star's brightness is preserved for a long time.
But how long does it take to form such a shell? In the course of the study, scientists studied two models. In one of them, a high-speed wind blew from the surface of the star, which slowly separated its parts, as a result of which the “cocoon” was formed over decades. In the second model, the star survived the explosion before a massive supernova explosion, sending huge amounts of material into orbit in less than a year.
The researchers then studied how the appearance of such material would affect the image of the star. When such a veil appears, it causes the luminary to dim.
Because scientists have images of stars decades before they went supernova, the researchers concluded that the slow transfer of matter model does not work. Otherwise, the star would be eclipsed.
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According to the researchers, this means that within a few years after a curtain of material appears around the star, it can explode as a supernova.
