Mystery of Betelgeuse's brightness may be closer to being solved

A light detection of this star, to which astronomers gave the designation Betelgeuse b, was made directly with one of the instruments of the VLT telescope, operated by the OES, Chile.

“ To be absolutely sure that this companion does exist we still have to observe her within a year when she is on the other side of the star [of Betelgeuse]. However, there is virtually no more room for doubt”, said, quoted in a statement from the OES, the study coordinator, Miguel Montargès, astronomer of the Paris Observatory in France.

The possible companion star of Betelgeuse, a star visible to the naked eye, was observed in December 2024.

Astronomers have been seeking explanations for the variation in Betelgeuse’s brightness for about a century.

The detection of what may be the companion star of Betelgeuse will lead scientists to investigate how it may affect the end of life of Betelgeuse, a red supergiant that should explode as a supernova.

“ The question of whether or not this companion will have an impact on the evolution of the red supergiant is truly open”, said Miguel Montargès.

The possible Betelgeuse b, from which astronomers will have been able to obtain “the clearest image ever”, has about two to three times the mass of the Sun and, according to the OES, is not bright.

The results of the discovery were published today in the scientific journal Astronomy & Astrophysics.