Explaining the anomalous behaviour of the famous supergiant star Betelgeuse, which has been keeping hundreds of scholars busy for decades, could be the presence of a companion that has so far remained invisible, as it has been obscured by the enormous brightness of the star itself: this hypothesis is put forward by a study currently being published in The Astrophysical Journal, led by the Centre for Computational Astrophysics of the American Flatiron Institute.
According to simulations carried out, the companion star would act as a small ‘snowplough’ that would periodically blow the dust away from Betelgeuse, thus producing its characteristic luminous ‘pulsations’: the discovery would therefore rule out the possibility that this behaviour could be a sign of the star's imminent explosion into a supernova, as previously thought.
Betelgeuse is a red supergiant, 100,000 times brighter than the Sun and 400 million times bigger: it is, in fact, the tenth brightest star in the night sky!
Astronomers can calculate how close it is to its end by measuring its ‘heartbeat’, i.e. its periodic variations that make it more or less brilliant, but herein lies the problem: Betelgeuse has two different beats, one repeating every year and the other every six years or so.
To solve the mystery, researchers led by Jared Goldberg have carried out new simulations of the phenomenon: the most likely explanation that has emerged is the proximity of a much smaller, Sun-like star, which would be responsible for the longer-lasting pulsations. “If there is no companion, it means that something much stranger is going on, something that is impossible to explain with current physics,” says Goldberg, who together with his colleagues now wants to hunt for the invisible intruder using telescopes.
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