Stardust or star bust? Betelgeuse's dimming light puzzles astronomers

James Marshall
February 17, 2020

Astronomers behind the new observations say while the star will go supernova at some point, the dimming is more likely caused by either a cooling of the surface or the ejection of dust blocking some of its light from Earth. Betelgeuse, a reddish star that is part of the Orion constellation, may be entering a pre-supernova phase - where it gets fainter before collapsing in a fiery explosion. As observed, the star is at about 36 percent of its normal brightness now compared to past year.

The supergiant star, under observation since December by the Sphere instrument of the ESO's Very Large Telescope facility at the Paranal Observatory in Antofagarta, Chile, began to dim in 2019 and is now at 36 percent of its normal brightness.

A press release issued by ESO on February 14 said the star is at about 36 per cent of its brightness at the moment, a change that is noticeable even to the naked eye. Due to this, astronomers and space experts think that the supergiant might be getting blocked by some debris or worse, it's going to explode soon- resulting in a Supernova.

Betelgeuse was born as a supermassive star millions of years ago and has been "dramatically" and "mysteriously" dimming for the last six months.

Even Earth Sky's Andy Briggs said that most astronomers believe that there are only small chances that an explosion will happen on Betelgeuse. And when they saw the before-and-after images, they noticed that Betelgeuse has also changed its shape. "Of course, our knowledge of red supergiants is still incomplete, and this is still a work in progress, so a surprise may still occur".

The star is over 700 light-years away from the Earth and is so big if it were placed where our Sun is in the Solar System it would stretch as far as Jupiter, engulfing all of the inner planets and the asteroid belt - that's before it explodes.

ESO's Very Large Telescope took this darkening view of Betelgeuse's surface in December 2019.

Betelgeuse's irregular surface is made up of giant convective cells that move, shrink and swell, ESO said.

'This is the only way we can understand what is happening to the star'.

A December image shows infrared light emitted by the dust, formed when material is shed into space, surrounding the star.

In the coming weeks, astronomers will be watching closely to see if Betelgeuse explodes.

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