A team of astronomers led by Hideyuki Sayo (Tohoku University) has discovered that Betelgeuse is much larger than previously thought, more than 1,200 times larger than the Sun. This means that the giant star may be running out of carbon fuel. "Once the carbon in the core is depleted, a core collapse is expected in a few decades, leading to a supernova explosion," the authors write.
Betelgeuse, one of the most famous stars in the night sky, is located in the constellation Orion and is a red supergiant. Its unusual behavior has caught the attention of astronomers because it may herald a nearby supernova explosion.
Observations show that Betelgeuse periodically changes its brightness and size. This is due to pulsations that occur within the star. The pulsations cause changes in its volume and temperature, which are reflected in the brightness and color we see from Earth.
The model created by Sayo and his colleagues simulates these pulsations and predicts how Betelgeuse's brightness will change in the future. They claim that their model accurately matches the observed data and provides a unique insight into the inner state of the star.
However, recent observations show that Betelgeuse has become significantly fainter over the past month. This has caused concern among astronomers, as this dramatic change in brightness could be related to an imminent supernova.
However, it is not yet possible to say for sure whether this is a precursor to a supernova or just a temporary change. Astronomers continue to study Betelgeuse, hoping to gather more data to better understand what is going on inside this mysterious star.
Betelgeuse, one of the brightest and most recognizable stars in the night sky, has long attracted the attention of astronomers for its rapid changes. It was described by Ptolemy as an orange-brown star, while Chinese observers saw it as yellow. Recently, astronomers have classified Betelgeuse as a red giant near the end of its life. This means that the star should explode as a supernova in the next hundreds of thousands or millions of years. Betelgeuse has also been found to pulsate, brightening and dimming over periods of a few months to several years.
In 2019, there was an unexpected dimming of Betelgeuse that caused concern among astronomers. They wondered if the star was approaching its supernova. However, further observations showed that the dimming was caused by a dust cloud and that Betelgeuse's supernova was still a considerable distance away.
Now, scientists from Tohuko University in Japan have come up with a new hypothesis. They have reanalyzed the data and concluded that Betelgeuse may be closer to its supernova than previously thought. They argue that the star is in the late stages of burning carbon in its core and could be the next galactic supernova.
To understand this hypothesis, it is necessary to know how stars change over the course of their lives. Stars are formed from gas, mostly hydrogen and helium. When these gas clouds collapse, the hydrogen nuclei fuse together, releasing enormous amounts of energy. This energy heats the star and prevents it from collapsing further. Eventually, however, the hydrogen fuel runs out and the star begins to burn heavier elements, such as carbon. This causes the star to expand, turn red, and eventually go supernova.
Betelgeuse is already in a late stage of carbon burning, suggesting that it may be closer to its supernova than previously thought. The star's pulsations also play an important role in this hypothesis. The pulsations cause the star to temporarily brighten and then dim. By measuring these pulsations, scientists can infer the star's mass and the fusion processes taking place in its core.
If the hypothesis is correct, Betelgeuse could become the next galactic supernova. This event will be observable from Earth and will provide astronomers with a unique opportunity to study the processes that occur during supernovae in nearby galaxies.