Astronomers Capture Clearest Image of Betelgeuse’s Companion Star

After nearly a hundred years of hunting, astronomers have caught a clear portrait of an ordinary star orbiting one of the most recognizable red supergiants in the night sky. Researchers used the Very Large Telescope located in the Atacama Desert region of Northern Chile to secure the strongest evidence yet that Betelgeuse is part of a binary system.

The target of this prolonged scientific quest is Betelgeuse, a blazing red supergiant marking the right shoulder of the constellation Orion. Situated roughly 650 light-years from Earth, the massive star has captured human attention for centuries due to its distinct orange-red hue and dramatic fluctuations in brightness.

Spotting the Elusive Companion With Exoplanet Tech

Catching sight of the elusive companion required borrowing specialized tools originally designed for an entirely different branch of astronomy. Researchers deployed the European Southern Observatory’s Very Large Telescope alongside its SPHERE instrument, which features a coronagraph that blocks out the blinding glare of a primary star to reveal fainter objects nearby.

That instrumental setup allowed the team to successfully isolate the dim light of the smaller star amid the intense illumination of the massive supergiant. Astronomers took clear images on two separate days in December 2024, capitalizing on predictions that the companion star would reach its furthest point from Betelgeuse during that month.

“It is remarkable to see how SPHERE and advanced post-processing techniques, originally developed to find exoplanets, also excel at detecting a companion around a massive, evolved star like Betelgeuse.”

Anthony Boccaletti, astronomer at the Observatoire de Paris

The resulting direct observations mark the clearest portrait obtained so far, following earlier theoretical models and hints collected over decades. While other teams had previously gathered evidence or attempted imaging—including potential detections with the Gemini North Telescope in Hawaii—the new VLT data provides the definitive look researchers needed.

Revising Mass Estimates and Solving a Century-Old Mystery

The discovery directly addresses a long-standing astronomical puzzle. Scientists originally proposed the existence of an orbiting companion roughly 100 years ago to explain Betelgeuse’s strange dimming cycles, which have been documented for more than a millennium. While short-term variations every few hundred days stem from internal pulsations, a longer six-year brightness cycle baffled researchers until recent orbital models pointed to an accompanying star.

Lead researcher Miguel Montargès of the Observatoire de Paris in France recalled the moment the processed data finally materialized.

“This is the conclusion of a century-long quest. We have shown that Betelgeuse is not single; it is accompanied by a faint stellar companion. I jumped from my chair when I saw the processed images.”

Miguel Montargès, team leader at the Observatoire de Paris

Intriguingly, the companion turned out to be much heavier than initial models predicted. While theorists originally suspected the star matched the mass of our sun, the new observations demonstrate that Betelgeuse B carries around 2 to 3 times the mass of the sun, with specific calculations placing it between 2.6 and 3.1 solar masses according to participating researchers.

“Honestly, I thought we did not have the sensitivity to detect Betelgeuse B as it was predicted. Because it is more massive than predicted, we see it!”

Miguel Montargès, astronomer at the Observatoire de Paris

Separating Binary Evolution From the Great Dimming

The confirmation of a companion star arrives just a few years after Betelgeuse sparked global speculation by undergoing the Great Dimming in late 2019, when the star lost about 60 percent of its normal brightness. That dramatic event triggered widespread rumors that the aging supergiant was on the verge of exploding in a spectacular supernova.

Subsequent observations by Montargès and other teams utilizing the Very Large Telescope clarified that the 2019 event had nothing to do with an impending stellar death. Instead, the red supergiant had blown off a giant piece of surface material—a surface mass ejection—that cooled into a dense dust cloud and temporarily obscured the star’s light before fully clearing by April 2020.

With the dust settled, researchers are now turning their attention toward understanding what role, if any, the newly imaged companion plays in the long-term lifecycle of Betelgeuse A.

“To be certain that the companion is really there, we still need to observe it in one year on the other side of the star, but there is very little space left for doubt. The question is truly open whether this companion is going to have an impact on the evolution of the red supergiant.”

Miguel Montargès, astronomer at the Observatoire de Paris

The research team published their findings in the journal Astronomy & Astrophysics, cementing a milestone for stellar astronomy. To secure absolute final confirmation and map the complete orbit, astronomers plan to observe the companion star again when it swings to the opposite side of Betelgeuse.