The red star of Betelgeuse is one of the brightest in our sky.
The supergiant in the constellation of Orion started to noticeably dim in October 2019.
Its brightness returned to its normal range in April 2023. However, across May and June 2023, its brightness increased by almost 50 per cent, which means it can be classed as a variable star.
Betelgeuse’s recent behaviour has led scientists to conclude that the star might have entered its final life stage and might go supernova in the near future.
But what is a supernova, why does a star’s brightness change, and why do scientists think the star might explode?
Here is everything we know.
What is a supernova?
A supernova is when a star’s brightness levels suddenly increase as a result of a catastrophic explosion.
It’s caused by a change in the core of the star. The change can either be caused by a star stealing too much matter from its companion star or because the star has run out of nuclear fuel, which causes some of its mass to flow into its core and collapse.
What causes a star’s brightness to change?
While Betelgeuse has shown that its brightness varies in its 400-day cycle, its recent brightness changes have been abnormal.
Astronomers believe that the star was initially dimmed because of a huge ejection of matter, which caused a dust cloud around it, making the supergiant more difficult to spot.
Why do scientists think Betelgeuse may explode?
A star’s life is spent converting hydrogen into helium as its fuel, a process that prevents it from collapsing under its own weight.
However, when a star runs out of hydrogen, the helium starts to burn into carbon, causing the star to swell. When all of the fuel is burned, the star is no longer able to carry its own weight and collapses into a solid neutron star.
A recent paper by Japan’s Tohoku University has concluded that Betelgeuse might be at the final stage of its life, which is the carbon-burning stage.
The leader of the study, Hideyuki Saio, believes that “the core will collapse a few tens of years after the carbon exhaustion”.
However, a group of researchers from Hungary’s Konkoly Observatory have shared that they believe the star is in the earlier helium-burning stage of its lifecycle.
Either way, it seems likely that Betelgeuse will be the Milky Way galaxy’s next supernova but this wouldn’t happen anytime soon. It could even be another 100,000 years before Betelgeuse’s light is finally extinguished.
