The red giant star is in the constellation Orion, 642.5 light years distant from Earth and was the ninth brightest star in the sky; a beacon in the night sky. It is a variable star, and it has been known to get dimmer and brighter, but the big surprise is that it still continues to dim, something that is unprecedented in the decades that astronomers have been observing the star. It is currently only the 24th brightest star in the sky.
Now, a team of astronomers has captured the unprecedented dimming of Betelgeuse thanks to images from the VLT (Very Large Telescope) telescope, which show not only the gradual fading of its brightness, but also how this star that will end is changing its apparent shape exploding as a supernova in the not too distant future. The truth is that the star and the surrounding area have changed dramatically throughout 2019.
Is Betelgeuse going to explode as a supernova?
Telescopes around the world have set their sights on Betelgeuse, taking this opportunity to see the star at such an unusual time. W hile it could go supernova any time in the next 100,000 years, the chances of us seeing it, in this lifetime, are incredibly remote.
Its variations are normal for Betelgeuse: it rises and falls as internal temperatures rise and fall, pushing the star in and out as if it were a beating heart. It has huge convective cells on the surface that boil creating brighter and dimmer regions, and it is constantly expelling dust that can temporarily obscure our vision.
The most recent images
Betelgeuse is so close and so large that ground-based telescopes can also view the star’s surface as a disk, seeing individual features such as huge convection cells. If you remember the convective cells that we recently saw in images of the Sun’s surface thanks to the Daniel K. Inouye telescope, they were hot gas droplets transported from the bottom of the star to the surface and released into space. On the surface of the Sun, they can be 1,000 km in diameter but on the surface of Betelgeuse, they can be as large as 60% the size of the entire star; thus the convection cells of this star can be hundreds of millions of kilometers in diameter.
But what is happening?
Betelgeuse has always been a variable star and there are a couple of potential causes. Both are related to the enormous size of the star; it has a tenuous gravitational grip on some of its outer layers, which have very heavy elements due to the star’s advanced age. The result is that it produces an exacerbated amount of cosmic dust, and it is possible that the dense cloud of dust between us and the star is responsible for its attenuation.
The other possibility would represent a process similar to sunspots, but on a much larger scale. It is possible that, due to the enormous distance already from the core and the area where the star’s magnetic field is generated, huge areas of the surface can be cooled simultaneously.
As it is, we have no idea whether Betelgeuse is going to explode anytime soon, but professional astronomers do not think this is the case at the moment. We will have to continue observing.
