Betelgeuse: Scientists solve puzzles about the red supergiant star that suddenly turns darker and is called “Great Dimming” | News from the UK
Scientists believe they have solved the mystery of why one of the brightest stars in the sky suddenly became visibly darker.
Betelgeuse – a red supergiant in the constellation of Orion – lost more than two-thirds of its brilliance, raising fears that the star is nearing the end of its life and is about to explode.
Astronomers were puzzled by the discovery dubbed “big dimming” in late 2019.
But an international team of researchers now believes that a cloud of stardust was responsible.
The team came to their conclusion after analyzing images of Betelgeuse over the years with the Very Large Telescope (VLT) of the European Southern Observatory (ESO) in Chile.
They revealed in the scientific journal Nature how the event was triggered by the formation of stardust that obscures half of Betelgeuse.
Miguel Montarges from the Observatoire de Paris, France, and KU Leuven, Belgium, the lead author of the study, added: “For once we saw a star change in real time over weeks.
“We witnessed the formation of so-called stardust directly.”
But Betelgeuse – which is about 500 light years from Earth – eclipsed only a few months before the star returned to its original lighting level in April 2020.
The star’s surface undergoes regular changes as giant gas bubbles move, shrink, and swell – a phenomenon known as pulsation.
Scientists believe Betelgeuse emitted a large bubble of gas when it was dimmed.
Shortly afterwards, when the star’s surface partially cooled, heavier elements in the gas, such as silicon, condensed into solid dust.
Professor Stefan Kraus of the University of Exeter, one of the authors of the study, added: “Aging stars like Betelgeuse have long been suspected of ejecting dust spots either from constant wind or more localized surface ejections.
“Here we see Betelgeuse ejecting a massive cloud of dust that obscured half of the star’s surface as it drifted into space.”
The scientists will continue to examine the star, which is around 1,000 times its size, to see how another gas bubble is ejected.
Study author and astronomer at the Harvard-Smithsonian Center for Astrophysics in the United States, Andrea Dupree, said the research “affects our understanding of the evolution of all stars.”