Astronomers using the European Southern Observatory’s Very Large Telescope have captured direct images of what is strongly predicted to be Betelgeuse B, a faint stellar companion orbiting the massive red supergiant star.
Searching for Betelgeuse B With the Very Large Telescope
A team of astronomers uncovered the strongest evidence yet that the red supergiant Betelgeuse, which marks the shoulder of the Orion constellation, is accompanied by a stellar companion. Researchers utilized the European Southern Observatory’s Very Large Telescope in Chile’s Atacama Desert to capture the clearest direct image to date of the suspected companion, utilizing the SPHERE instrument originally developed to find exoplanets.
Scientists have hunted for Betelgeuse B for roughly a hundred years. Predictions indicated that the hypothetical partner would reach its furthest orbital point from the primary star in December 2024, providing a crucial observation window for researchers to gather and process data. The target was also potentially detected using the Gemini North Telescope in Hawaiʻi, USA, in 2025, according to observations that employed the ‘Alopeke instrument.
Speckle Imaging and the Gemini North Telescope Breakthrough
While large ground-based telescopes offer the sharp vision necessary to separate closely spaced objects, they face severe distortion from Earth’s atmosphere. To overcome this atmospheric blurring, a team led by Steve Howell of NASA’s Ames Research Center turned to an 8.2-meter Gemini North telescope in Hawaii and applied speckle imaging. This specialized technique combines multiple ultra-short exposures to freeze atmospheric twinkle and build a sharper composite image.
Independent analyses of decades-long brightness variations and positional jitters had previously led two separate research groups to conclude that the giant star possessed a small companion. However, the immense size and overpowering brightness of Betelgeuse left remaining doubts about whether a smaller partner could ever be visually detected. Space-based observatories including NASA’s Hubble Space Telescope and the Chandra X-ray Observatory previously found no trace of the object.
Mass, Brightness, and Unexpected Properties
Initial theoretical models suggested that Betelgeuse B was roughly as massive as the Sun. The latest direct observations, however, indicate that the companion is two to three times as massive as the Sun, while separate evaluations estimate it as a young, hot star roughly 1.5 times solar mass positioned deep within the red supergiant’s outer atmosphere.
“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, lead author via Sky at Night Magazine
The presence of a companion offers a physical explanation for long-standing mysteries surrounding Betelgeuse, including its puzzling 6-year brightness pulsation cycle and its abnormally fast rotation rate. Gravitational forces from an orbiting partner can spin up a primary star over time, though such interactions require the companion to sacrifice orbital separation.
Supernova Timeline and Future Observations
Betelgeuse has exhausted its internal hydrogen fuel and now burns helium, causing the star to swell to gargantuan proportions. If placed at the center of our solar system, its surface would extend outward to the orbit of Jupiter. Global attention spiked in 2019 when the star dimmed dramatically, sparking intense speculation that a supernova explosion was imminent—an event not witnessed in the Milky Way galaxy for four centuries. That dimming was subsequently traced to an erupted cloud of gas and dust that cooled and blocked the light.
Researchers emphasize that further verification is required before the discovery is considered absolute. Astronomers plan to track the system as the companion moves to the opposite side of the primary star.
Looking further ahead, gravitational dynamics are expected to draw the two bodies closer together. Researchers predict that the companion will eventually drift inward and merge with Betelgeuse within the next 10,000 years, while the red supergiant itself is expected to exhaust its heavy elements and detonate as a supernova within the next 100,000 years.
