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Wednesday, 16 June 2021

Never-before-seen images of 10th brightest star Betelgeuse reveal its October 2019 'Great Dimming' was caused by a massive dust cloud

  • Betelgeuse is a bright orange star that sits 700 light years away from Earth
  • It is the 10th brightest star visible from our planet  
  • It dimmed in October 2019, with experts wondering if it was about to explode 
  •  New research captured two new images of the star from 2020 
  • These were compared with images snapped the star in 2019
  • Scientists were able to see how  Betelgeuse's brightness changed over time
  • The dimming was caused by a massive dust cloud blocking the star's lightNever-before-seen images of Betelgeuse, a bright orange star in the constellation of Orion, have solved the mystery of what caused its ‘Great Dimming’ in 2019.

    A team of international scientists found the massive star ejected a large gas bubble, which cooled and formed a dust cloud that temporarily blocked the star's light.  

    Prior to Tuesday's announcement, some experts believed that Betelgeuse was on the verge of exploding when irregular dimming patters were observed in October 2019.

    However, the new images have solved the mystery by allowing scientists to clearly see how the star's surface changed and darkened over time. 

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    The team captured two never-before-seen images of Betelgeuse's surface in January and March 2020, which were then compared to those taken in January and December 2019. This allowed them to see changes in real-time and determine ¿this abrupt dimming was caused by the formation of stardust'

    The team captured two never-before-seen images of Betelgeuse's surface in January and March 2020, which were then compared to those taken in January and December 2019. This allowed them to see changes in real-time and determine ‘this abrupt dimming was caused by the formation of stardust'

    The team, led by Miguel Montarg├Ęs at the Observatoire de Paris, captured two never-before-seen images of Betelgeuse's surface in January and March 2020, which were then compared to those taken in January and December 2019. 

    This allowed them to see changes in real-time and determine ‘this abrupt dimming was caused by the formation of stardust,’ the team shared in a statement. 
    News of Betelgeuse dimming first surfaced in December 2019, after scientists made it public they had witnessed an irregular dimming pattern in October.

    It was initially believed that this dimming was the start of Betelgeuse going going supernova - when a star explodes at the end of its life, producing the brightest flash ever seenThese findings match those uncovered by Andrea Dupree, associate director of the Center for Astrophysics at Harvard & Smithsonian, in the summer of 2020. Dupree also suggested the dimming was caused by a massive dust cloud

    These findings match those uncovered by Andrea Dupree, associate director of the Center for Astrophysics at Harvard & Smithsonian, in the summer of 2020. Dupree also suggested the dimming was caused by a massive dust cloud

    At this point, the star runs out of nuclear fuel, some of its mass flows into its core that becomes too heavy to withstand its own gravitational force.

    And the core finally collapses, which results in the giant explosion of a supernova. 

    Dr. Malcom Davis, a senior analyst at Australian Strategic Policy Institute, tweeted in 2019: ‘Betelgeuse is dimming, which is an indication that it will go supernova soon - when we don’t exactly know.

    Betelgeuse is a bright orange star in the constellation of Orion and sits 700 light years from Earth

    Betelgeuse is a bright orange star in the constellation of Orion and sits 700 light years from Earth

    THE FIVE STAGES OF THE DEATH OF A STAR 

    1. Just before explosion 

    At the end of its life there is no more fuel so it collapses under its own weight 

    2. The first light flag 

    The core collapses and sends a shock wave out into space and for a few hours the shock compresses and heats, producing a very bright flash.

    3. The flash has gone 

    After hitting the surface of the star the shock blows it apart and the core turns into a neutron star 

    4. The proper supernova 

    The hot glowing surface expands quickly, making the fireball brighter again and will be up to 10x the size of the original star in a few days. This is when we'll see it. 

    5. A long time after 

    The remains of the former star are spread over light years of space leaving a faint glow behind 

    SOURCE: Keele University 

    ‘When it happens (it would have actually happened ~690 years before we see it on Earth given the star’s distance) it will be as bright as the full moon.’

    Since the ‘Great Dimming’ was observed, scientists have been tirelessly working to determine if Betelgeuse was heading toward supernova or if there was another explanation to this mysterious dimming.

    Now, Montarg├Ęs and his team have found that it was caused by the star ejecting a large gas bubble that moved away from it, aided by the star’s outward pulsation.

    When a patch of the star's surface cooled down shortly after, that temperature decrease was enough for the heavier elements in the gas, such as silicon, to condense into solid dust.

    These findings match those uncovered by Andrea Dupree, associate director of the Center for Astrophysics at Harvard & Smithsonian, in the summer of 2020.

    ‘With Hubble, we see the material as it left the star's visible surface and moved out through the atmosphere, before the dust formed that caused the star to appear to dim,’ Dupree shared in an August 2020 NASA release.

    'We could see the effect of a dense, hot region in the southeast part of the star moving outward.'

    Dupree found that the material moved about 200,000 miles per hour as it traveled from the star’s surface to its outer atmosphere.

    Once the gas bubble was millions of miles from the hot star, it cooled and formed a dust cloud that temporarily blocked the star’s light.

    Betelgeuse, which sits 700 light years from Earth, returned to its normal brightness by April 2020. 

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