Astronomers find clear evidence that Betelgeuse star 'is not single'
The best evidence of the existence of the companion star was published in a study on Tuesday, based on observations by the European Southern Observatory's Very Large Telescope (VLT) in Chile.
"This is the conclusion of a century-long quest," lead study author Miguel Montarges, of the Paris Observatory, said in a statement.
"We have shown that Betelgeuse is not single, it is accompanied by a faint stellar companion."
Betelgeuse is a a red supergiant star, known to many as the hunter's shoulder in the Orion constellation.
Records suggest that thousands of years ago, ancient Egyptians and Indigenous Australians noticed that the star's brightness changed in regular cycles.
The reason for this flickering remained a mystery until astronomers in 2024 posited that it was caused by the crossing of a much-smaller companion star.
Betelgeuse B
Astronomers had feared that the VLT would not be able to spot the companion because it would be blinded by the light from Betelgeuse, which is 1,000 times bigger than the Sun.
The companion star – Betelgeuse B – had been thought to have only 1.5 times the Sun's mass.
"I jumped from my chair when I saw the processed images," Montarges said.
It turned out that the companion was significantly heavier than had been believed, weighing two to three times more than the Sun. Using ESO's Very Large Telescope, astronomers have obtained the clearest image yet of Betelgeuse B, a star orbiting Betelgeuse.
The observations were taken in December 2024, when the companion star was farthest away from Betelgeuse.
However it took a long time to process and analyse the data, the results of which were published in the journal Astronomy & Astrophysics.
While more observations are needed to definitively prove the companion's existence, "there is very little space left for doubt," Montarges said.
Betelgeuse previously surprised astronomers by dramatically dimming for five months between 2019 and 2020.
Scientists first thought the change meant the star would soon die in an epic supernova explosion.
However, further observations revealed the dimming was caused by a massive amount of material ejected from the surface that created a dust cloud which blocked the star's light.
(with AFP)