The days of the super giant red star would be numbered, according to new research that analyzed its pulsations. The spectacular explosion could take place within a few decades.
Betelgeuse is dying. The old red star that is just over 650 light years from Earth will have, in a few decades, its “last function” in a spectacular explosion that we can see with the naked eye both day and night.
This is predicted by scientists from Tohoku University in Japan and the University of Geneva in Switzerland who made a new forecast about the condition of Betelgeuse based on its pulsations. The work was published on arXiv.
He had already given some sign of his condition, although at that moment the specialists were confused. It was in 2019 when its brightness dimmed significantly for a while.
But the red supergiant, which is about 20 times more massive than our Sun and about 1,000 times larger, peaked as bright as one and a half times as bright as usual earlier this year.
That once again sparked speculation about the fate of the Orion constellation superstar: were the changes a death rattle or just the palpitations that come with old age?
Once a hot, heavyweight beast known as an O-type star, Betelgeuse follows the credo of burn fast, die young, having come into existence a mere 10 million years ago.
Already a swollen red ball that is running out of fuel, its years are numbered. How fast your final outcome will be depends on a lot of factors. And it is here where the lucubrations are fed.
One of those factors, and perhaps the most important, is its actual size, which has been the subject of debate for much of the 20th century.
With recent measurements placing it at the more compact end of the estimates, the star likely has many tens of thousands of years to go before it finally cools enough to implode.
But there are other reasons to think that Betelgeuse is well enough to have some way to go.
Like many stars, its outer layers pulsate in a balance of contraction and expansion driven by competing internal dynamics of pressure and gravity.
The resulting fluctuations in brightness hum at frequencies that take months or even years to repeat themselves; in the case of Betelgeuse, its two most notable periods are approximately 2,200 and 420 days.
The shorter period has generally been considered the dominant “beat” of this enormous heart, which represents an oscillation around the entire circumference of the star in what is known as its radial fundamental mode.
Calculations based on this relatively rapid expansion and contraction are what we might expect for a slightly smaller, and therefore younger, O-type star.
But the researchers behind this latest research are not so quick to dismiss the much slower pulse as a so-called long secondary period, arguing that the thermodynamics behind the oscillations in luminous supergiants like Betelgeuse are a bit more complicated than in most. other stars.
If the star were to squeeze atomic nuclei into slightly larger elements, such as carbon, it could handle a much longer radial pulsation period. Where shorter-duration radial modes would put Betelgeuse’s radius at around 800 to 900 times that of our Sun, the team showed how the longer pulse would be consistent with a radius of around 1,300 times.
That means Betelgeuse’s outer layers are drifting farther apart as its mass is concentrated in its core, churning fuel at a rate fast enough that its engines will stall not for millennia, but decades.
Although it has yet to go through peer review, the study is enough to remain somewhat optimistic that we could still observe a supernova with modern instrumentation in our lifetime.
Source: Science Alert