What is the Betelgeuse Supernova explosion? All about the odd supergiant star brightening up

Betelgeuse, the bright, red star of the Orion constellation, has been showing some unexpected behavior, with some suggesting that it will explode soon. The seventh brightest star in the sky, Betelgeuse became fainter in late 2019 and 2020 than it was previously recorded.

However, it has become bright again and the brightest in the Orion, probably the most visible ever seen in the sky. Not only is Betelgeuse a red supergiant, but it also pulsates as a semiregular variable star. There appears to be a certain degree of frequency in the variations of its brightness, although the levels may fluctuate.

With an approximately 400-day cycle, the brightness of the object undergoes changes. The celestial body boasts three distinct cycles, each determined by its pulsations. These cycles include a brief 125-day cycle, a moderate 230-day cycle, and an impressive 2200-day cycle.

At times, a star can get very bright for a short time. Supernovas are the biggest and rarest of these types of stars. They are made when a whole star ends its life in a big explosion. Supernovas have only occurred a few times in the previous 1,000 years, yet they may be brilliant enough to be seen during the day.

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Betelgeuse Supernova explosion could happen sooner than later

Now that the Betelgeuse is brightening up again, it has caught the attention of scientists who are curious about the star's evolutionary stage and what will such activity result in. A new paper titled "The evolutionary stage of Betelgeuse inferred from its pulsation periods" argues that the star could explode as a supernova at a sooner time than expected.

In the paper, whose first author is from Japan's Tohoku University's Hideyuki Saio, the researchers argue that Betelgeuse could be the next supernova of the Milky Way.

“We conclude that Betelgeuse is in the late stage of core carbon burning, and a good candidate for the next Galactic supernova.”

The study suggests that the star, a red supergiant, has departed from the main sequence. Over the course of its extensive 8 to 8.5 million-year lifespan, this entity utilized plenty amounts of hydrogen through the process of fusion, converting it into helium and expelling the resulting mass as energy.

It just means that the star is not converting hydrogen to helium anymore, unlike the Sun. When stars like Betelgeuse lose mass, their gravity is no longer strong enough to hold in the pressure from the outside, so they grow bigger. So, even though they lose weight, they get bigger.

Things change when stars like Betelgeuse stop fusing hydrogen and helium into their core. Carbon accumulates in their cores during the subsequent helium fusion stage. Then they start a core carbon-burning stage, which generates additional elements.

The authors of the latest study state that the star is actually at the end of its lifetime. However, they do not have an exact timeline as to when the star could experience a supernova explosion. The researchers wrote:

“Despite the relatively small distance from Earth, and in some sense because of it, it has been difficult to obtain tight constraints on the distance, luminosity, radius, current and Zero Age Main Sequence (ZAMS) masses, and information about the internal rotational state and associated mixing and hence on the evolutionary state of the star and when it might explode.”

As per The Conversation, if the star in question goes supernova, it would be harmless to us since it's around 500 light-years away. The initial scenario would consist of a shower of neutrinos, which are weightless particles that pose no threat to humans. Following that, the star would rapidly increase in brightness.

In a span of one to two weeks, it is expected to radiate with a brightness equivalent to that of the full Moon. The star would then fade over the coming months but will remain visible during the daytime for up to 12 months.

At night, it would also be visible for at least two years, but post that, won't be visible in the sky.