Astronomers Say They’ve Finally Spotted Betelgeuse’s Companion Star, Long Predicted to Exist but Never Seen

The discovery, if confirmed, could explain Betelgeuse’s mysterious six-year oscillations in brightness

Sara Hashemi

– Daily Correspondent

July 22, 2025 4:52 p.m.

Scientists have long speculated that Betelgeuse, one of the brightest stars in the night sky, is not alone. Now, thanks to the powerful Gemini North Telescope in Hawaii, astronomers suggest they’ve spotted Betelgeuse’s elusive companion—a smaller star in a tight orbit around it, both sitting at the shoulder of the constellation Orion.

The discovery could help explain some of Betelgeuse’s mystifying behaviors and shed light on the star’s possibly doomed future. The findings are to be published in The Astrophysical Journal Letters later this week.

Betelgeuse is a red supergiant star close to the end of its life, as it’s rapidly burned through all of its hydrogen fuel and is now burning helium instead. The companion star, on the other hand, is in such an early phase that it hasn’t even started burning hydrogen.

“Isn’t that crazy?” says study lead author Steve B. Howell, a scientist at NASA Ames Research Center, to Robin George Andrews at the New York Times. “It’s kind of crazy.”

Betelgeuse’s companion—sometimes called the Betelbuddy—will likely meet a quick end. Once Betelgeuse runs out of fuel, it’ll explode into a supernova and take its companion out with it. And if it’s not engulfed by an exploding supernova, Betelbuddy won’t be spared a violent death. Because of its proximity to the dying supergiant star, gravitational forces will cause Betelbuddy to spiral into Betelgeuse within the next 10,000 years, per a statement from the National Science Foundation’s NOIRLab.

The new research includes a visual of the star captured by an imager mounted on Gemini North called ‘Alopeke, which means fox in Hawaiian. The image is faint, though, and even the study authors note that further observations are needed to confirm the discovery.

“I think at this point it’s quite tough to say whether or not the detection is believable,” says Sarah Blunt, an astronomer at the University of California, Santa Cruz, who was not involved with the study, to Mara Johnson-Groh at Science News. “We’ll have to wait and see if the companion can be confirmed with more instruments.”

Jared Goldberg, an astronomer at the Flatiron Institute who was not involved in the work, echoes that sentiment to Daniel Clery at Science. “I think future observations are needed when the companion comes back into view,” he says.

If they’re verified, the findings offer a possible answer to a mysterious six-year variability in Betelgeuse’s brightness. Scientists had suggested that a companion star may be the cause for its brightening and dimming but have failed to observe it with both NASA’s Hubble Space Telescope and the Chandra X-ray Observatory, per the statement.

These new images are the best proof of a companion thus far. “It’s incredible that they found it,” says Miguel Montargès, an astronomer at the Paris Observatory who was not involved in the research, to the New York Times.

The astronomers captured their images with an uncommon technique known as speckle imaging. It involves using short exposure times to remove distortions caused by the Earth’s atmosphere. When the team stacked these images together, the high-resolution result revealed Betelgeuse’s companion.

“This detection was at the very extremes of what can be accomplished with Gemini in terms of high-angular resolution imaging, and it worked,” Howell says in the statement. “This now opens the door for other observational pursuits of a similar nature.”

The Betelbuddy is predicted to have around 1.5 times the mass of the sun, and the distance between the stars is about four times the distance between the sun and Earth. The companion star orbits so close to Betelgeuse that it moves through its outer extended atmosphere, completing one loop every five or six years.

Astronomers will have another chance to study Betelgeuse’s companion in 2027, when it’s expected to be farthest from Betelgeuse and easier to detect.