Betelgeuse B Companion Star Confirmed by ESO Observations

Astronomers have presented the most convincing evidence yet that the red supergiant Betelgeuse, the bright shoulder of the Orion constellation, is not solitary. A study published in *Astronomy & Astrophysics* and coordinated by the European Southern Observatory (ESO) reports an image compatible with a previously hidden companion, dubbed Betelgeuse B, captured with ESO’s Very Large Telescope. The companion is estimated to have a mass comparable to the Sun and to orbit extremely close to Betelgeuse’s expanded surface, a configuration that would make it difficult to detect directly.

The discovery helps explain a long‑term brightness modulation of Betelgeuse that repeats roughly every six years, a pattern that has puzzled astronomers for decades. Observations were led by astronomer Miguel Montargès of the Paris Observatory, taking advantage of a favorable orbital window at the end of 2024 when the companion is expected to be slightly farther from the supergiant. The finding adds a new dimension to the study of massive stellar evolution and the dynamics of binary supergiant systems.