The Orion constellation star Betelgeuse might actually be two separate stellar bodies, a shocking new study has suggested

Most of the stuff in the night sky will appear indistinguishable from each other to the vast majority of us. However, most of us will also be able to consistently point out the Orion constellation after someone brings it to our notice, primarily because of how recognisable the cluster is. Despite Orion’s apparent stardom and popularity, scientists may have gotten something terribly wrong about the character of one of its brightest constituents, it turns out.

Betelgeuse, the left “shoulder” of Orion, has always been a star of intrigue. Look at it long enough (and we mean generations-long), and you’ll notice its strange pattern: dimming and brightening over a roughly 400-day cycle. Astronomers chalk this up to the star’s swelling and shrinking, a standard practice among stellar beings driven by the turbulent bubbling of gas near its core. This was all fine and well until something else came into view — a much slower heartbeat pulsing every 2,170 days, leaving scientists scratching their heads.

This "long secondary period" (LSP), as the experts call it, doesn’t quite fit with the usual behaviour of Betelgeuse. Was it dusty clouds? Strange magnetic fields? None of the usual suspects seemed to fully explain what was going on. That’s where things get interesting.

Enter "Betelbuddy"

Co-author Meridith Joyce and her team have proposed an out-of-this-world theory: Betelgeuse may have a partner, affectionately dubbed "Betelbuddy." This sun-sized companion star could be responsible for Betelgeuse’s mysterious LSP. According to the team’s calculations, Betelbuddy occasionally passes through the thick clouds of dust surrounding Betelgeuse. When it does, it clears the dust away, making Betelgeuse appear brighter from Earth.
What’s especially tantalising about this theory is that, while Betelbuddy could be a typical companion star, there’s also the wild possibility that it might be something much denser — perhaps a collapsed neutron star. But if Betelbuddy were indeed a neutron star, we’d expect to see X-ray emissions, which haven’t been observed yet. So, the jury’s still out.

A stellar mystery waiting to be solved

While the notion of Betelgeuse being part of a binary star system is still a hypothesis, it’s not entirely far-fetched. Many stars are known to have companions, and Betelgeuse might just be one more addition to this interstellar family.
Verifying the existence of Betelbuddy won’t be easy. The technology to detect such a companion is still being refined, but astronomers are gearing up for some key observations later this year. Perhaps we’ll soon know if this iconic red supergiant is truly sharing the stage.

The study has been published in a pre-print journal and can be accessed here.