Plate Nº 58 · recorded October 10, 2026
Space & AstronomyReported finding
Astronomers image Betelgeuse's hidden companion after century-long search
ESO's Very Large Telescope has captured the clearest image yet of a candidate companion to Betelgeuse, ending a 100-year search. The faint star weighs 2–3 times the Sun, far above earlier predictions.
By Marcus Bennett4 min read711 words
In brief
- Astronomers published the clearest image yet of Betelgeuse B on August 27, 2026 in Astronomy & Astrophysics.
- The candidate companion has a mass of about 2 to 3 times the Sun, versus earlier estimates near 1 solar mass.
- The VLT observations were taken in December 2024, when 2024 models predicted maximum separation from Betelgeuse.
- The search for a Betelgeuse companion began roughly 100 years ago.
- A follow-up observation in about a year is still needed to confirm the object on the opposite side of its orbit.
Astronomers have captured the clearest image yet of a candidate companion star orbiting Betelgeuse, ending a roughly 100-year search, researchers reported on August 27, 2026 in the journal Astronomy & Astrophysics.
The faint companion, nicknamed Betelgeuse B, shows up in observations taken with the SPHERE instrument on the European Southern Observatory's Very Large Telescope (VLT) in Chile's Atacama Desert. A team led by Miguel Montargès of the Observatoire de Paris–PSL used the telescope in December 2024, when models predicted the suspected partner would sit farthest from the bright red supergiant.
"I jumped from my chair when I saw the processed images," Montargès said.
How did astronomers finally spot it?
The possibility of a Betelgeuse companion first surfaced about a century ago, when researchers tried to explain the star's slow brightness changes with a hidden orbital partner. Despite repeated observations, no one clearly saw it.
Two studies published in 2024 sharpened the hunt. They predicted that Betelgeuse B would reach its greatest apparent separation from its host in December 2024, giving telescopes their best window. Montargès and colleagues pointed the VLT at Betelgeuse that month, then spent several months cleaning up the data.
"Honestly, I thought we did not have the sensitivity to detect Betelgeuse B as it was predicted," Montargès said. "Because it is more massive than predicted, we see it!"
The team directly imaged the companion, meaning they recorded light from the object itself rather than inferring its presence indirectly. Earlier hints had come from a possible detection with the Gemini North Telescope in Hawaiʻi, but the VLT data provide the strongest evidence so far.
Why is the companion so surprising?
Earlier estimates placed Betelgeuse B at roughly one solar mass, similar to our Sun. The new observations suggest it weighs about 2 to 3 times the Sun, with a brightness that pushed it above the team's detection threshold.
The find is striking because Betelgeuse ranks among the most-watched stars in the sky. A reddish point in the constellation Orion, it is visible to the naked eye and has been tracked for thousands of years.
"The fact that we can still discover a nearby companion, more massive and brighter than the Sun, around such a well-studied star is remarkable," Montargès said. "These are among the best moments in science: seeing something new, unexpected."
Co-author Anthony Boccaletti, also at the Observatoire de Paris, credited the SPHERE instrument and modern image-processing tools. "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," Boccaletti said.
Could the companion change Betelgeuse's fate?
Betelgeuse is a red supergiant near the end of its life, a stage in which massive stars swell and eventually explode as supernovae. Astronomers widely expect the star to detonate sometime in the next tens of thousands of years, though the exact timing remains uncertain.
The star drew global attention several years ago after a dramatic dimming episode. Montargès's earlier work, also using the VLT, showed the dimming came from a cloud of dust blocking part of Betelgeuse's light, not from any prelude to an explosion.
The newly imaged companion adds another variable. Researchers will now study whether Betelgeuse B can:
- strip material from the red supergiant
- alter how it sheds mass as it ages
- affect the timing or shape of its eventual supernova
"The question is truly opened whether this companion is going to have an impact on the evolution of the red supergiant," Montargès said.
What still needs to happen?
Astronomers treat the detection as a candidate, not a confirmed companion. To verify, they want to image Betelgeuse B again in roughly a year, when its predicted orbit should carry it to the opposite side of the red supergiant.
"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," Montargès said.
The study, titled "VLT/SPHERE images the candidate companion of Betelgeuse," appears in Astronomy & Astrophysics. Its 13 co-authors come from institutions in France, the Netherlands, Chile, the United States, Germany and Belgium.
via iopscience.iop.org (Original)
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