Betelgeuse Is Not Alone: Astronomers Have the Image to Prove It

Betelgeuse is one of the most studied stars in the sky. It sits at the shoulder of the constellation Orion, visible to the naked eye, and has been observed by astronomers for centuries. For roughly 100 years, researchers have suspected it was not a solitary star but a binary system — accompanied by a smaller companion in a long, slow orbit. In July 2026, a team led by astronomer Miguel Montargès of the Paris Observatory published the clearest image ever obtained of that companion. After a century of searching, the evidence is now direct.

Why Astronomers Suspected a Companion in the First Place

Betelgeuse is a red supergiant — a massive star nearing the end of its life. It is enormous by any measure: if placed at the center of our solar system, its outer layers would extend roughly to the orbit of Jupiter. Its brightness changes over time, and those changes follow several overlapping cycles. One of them, with a period of around six years, has long resisted a straightforward explanation based on the star’s internal physics alone.

In the 1980s, astronomers began proposing that a companion star in a roughly six-year orbit could account for this cycle. The idea gained support over the following decades as additional modeling and indirect measurements pointed consistently in the same direction. Two studies published in 2024 went further, predicting not just the companion’s existence but the geometry of its orbit — including the precise moment when it would be at its maximum angular separation from Betelgeuse as seen from Earth, making it easiest to detect.

That window opened in December 2024. Montargès and his team were ready.

The Observation and What It Took to Make It

The observations were taken on December 3 and 6, 2024, using the SPHERE-ZIMPOL instrument on ESO’s Very Large Telescope, located in Chile’s Atacama Desert. SPHERE is an extreme adaptive optics system originally developed for the direct imaging of exoplanets. It is designed to suppress the overwhelming glare of a bright central object and detect faint sources nearby — a capability that proved equally applicable here.

The core challenge was one of contrast. Betelgeuse B, the candidate companion, is approximately 30,000 times dimmer than Betelgeuse itself. Detecting it required the team to subtract Betelgeuse’s contribution from the image, pixel by pixel, over months of data processing. When the processed images finally revealed a faint point of light at the predicted location, lead author Montargès described running to share the result with a colleague: “I jumped from my chair when I saw the processed images.”

The result was published on July 28, 2026 in the journal Astronomy and Astrophysics.

What the Image Reveals About Betelgeuse B

The new observations provide the most detailed picture yet of Betelgeuse B’s properties. Key findings from the study include:

• Betelgeuse B has an estimated mass of 2.6 to 3.1 times that of the Sun — larger than earlier models had predicted
• The companion is separated from Betelgeuse by approximately 6 to 9 astronomical units, comparable to the distance between the Sun and Saturn or Uranus
• Its orbital period is consistent with the roughly six-year brightness cycle that first led astronomers to propose its existence
• The imaging technique used — borrowed from exoplanet astronomy — successfully separated the companion’s light from the enormous glare of Betelgeuse itself
• A second observation, planned for late 2027 when the companion is expected to appear on the opposite side of Betelgeuse, will be needed to confirm gravitational binding and fully rule out the possibility that the detected object is a background star

Co-author Anthony Boccaletti, also of the Paris Observatory, noted that it was “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.”

What This Changes — and What Comes Next

The confirmation of Betelgeuse B raises immediate questions that go beyond the star’s brightness variations. Betelgeuse is widely expected to end its life in a supernova explosion, though when exactly that will happen remains uncertain — it could be within the next hundred thousand years. The presence of a companion introduces new variables into that calculation.

A companion star at this distance could potentially interact with Betelgeuse’s outer layers as the supergiant expands further in its final evolutionary stages. It may influence the shape of the eventual supernova explosion, or alter the mass-loss patterns that precede it. As Montargès noted after the publication: “The question is truly opened whether this companion is going to have an impact on the evolution of the red supergiant.”

The companion has been given a formal name: Siwarha, meaning “her bracelet” in Arabic — a reference to Betelgeuse’s own Arabic name, which translates roughly as “hand of the giant.”

The next observation window, expected in late 2027, will be watched closely. If Siwarha appears on the opposite side of Betelgeuse as predicted, the binary interpretation will become effectively certain.