Betelgeuse is not alone: the red giant’s companion star has been discovered
A team of astronomers from the Paris Observatory has used the VLT to capture an image of Betelgeuse’s stellar companion: a historic breakthrough that explains the mysterious fluctuations in brightness of Orion’s supergiant
For almost a century, Betelgeuse has been the subject of astronomers’ scrutiny. Now, at last, one of its most fascinating aspects seems to have been clarified: Orion’s famous red giant is thought to have a companion, which is much fainter and smaller.
The discovery was made by a French research team, which used ESO’s Very Large Telescope, situated in the Chilean Andes, in the Atacama Desert. This is an important finding, because Betelgeuse is no ordinary star: it is one of the best-known stars in the winter sky, easily recognisable to the naked eye due to its reddish-orange colour and its position high in the constellation of Orion.
In Western tradition, Orion was the great hunter carrying a sword and the skin of a lion he had just slain. The star marking his right shoulder is none other than Betelgeuse, which has always been a subject of interest for at least two reasons: its variable brightness and its status as a red supergiant, destined sooner or later – in astronomical terms, so perhaps tomorrow or in 10,000 years’ time – to end its evolution as a supernova.
Betelgeuse is located approximately 650 light-years from us and has been observed for over a century in the hope of confirming the hypothesis of the existence of a stellar companion. For a long time, this was the most convincing explanation for the star’s variations in brightness: a faint companion passing close by is a more plausible hypothesis, at least from an observational point of view, than a cloud of gas orbiting the red giant.
In recent years, the theory that Betelgeuse B is a binary star has been supported by increasingly strong evidence. Now, thanks to an image obtained in collaboration with the French team, the evidence appears much more compelling.
