For hypergiant stars, the end is violent


Betelgeuse is one of those stars that astronomers refer to as hypergiants. And a few months ago they believed they were in the front row in his end of life. Lack. So they turned to another hypergiant star, “A Betelgeuse on steroids”to try to unravel the mysteries of the death of these star clocks.

Remember. It was the end of 2019, the beginning of 2020. Betelgeuse, one of the brighter stars of our sky, he had dramatically lost his brightnesswithout the astronomers understand why. They once thought we were about to witness the death of thesupergiant star. At the beginning of its supernova explosion. But it wasn’t. Betelgeuse has finally regained her splendor.

And the stars the supergiants have continued to keep part of the secret, which researchers at the University of Arizona (United States) hope to unravel thanks to the three-dimensional image of a hypergiant star. An image that reveals the processes that accompany the death of these extraordinary objects.

Of hypergiant stars, there are only a few. Only a few in the vastness of our Milky Way. Betelgeuse is one of them. VY Canis Majoris (VY CMa) is another. As the name suggests, it is found in the constellation of the Great Dogto just over 3,000 light years of our Earth. Its diameter is 10 to 15,000 times the Earth-Sun distance. It could be the most massive star in the Milky Way. “Like a Betelgeuse below steroidsComments LuciaZiurys, researcher, in a University of Arizona statement.

No supernova for hypergiant stars?

It is these extraordinary features that prompted astronomers to examine the case of VY Canis Majoris. With the aim of verifying whether these star monsters actually evolve into supernovae. “If so, we should see many more supernovae in the sky”, says Lucy Ziurys. That’s why the researchers believe that at least some may simply collapse in silence black holes .

Unlike less massive stars, hypergiant stars tend to suffer loss of massconsistent and sporadic forming complex and very irregular structures. Types of arches, tufts or knots . To learn more about VY CMa and how it loses mass – this was confirmed by the observations of the Hubble Space Telescope in particular – the astronomers have tracked down, thanks to the data of the Large array of millimeter / submillimeter antennas of the Atacama (Chile), some molecules – the dioxide of sulfur (N / A2), the oxide of silicon (SiO) or chloride of sodium (NaCl) – ejected from the surface of the star. By moving Alma’s antennas, they were also able to get very detailed information on directions and gearsmovement of these molecules.

The researchers then superimposed this on pre-existing images of the surrounding dust VY Canis Majoris. And what they observed, is not in fact a symmetrical loss of mass, but many cells of convection. Like giant balls ejected in different directions. “A bit like the coronal arches we observe on ours Sun. But a billion times bigger “concludes Lucy Ziurys.

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