Updated

Updated · Earth.com · Aug 9

Astronomers Photograph Betelgeuse B at 52 Milliarcseconds, Backing 2,200-Day Binary Theory

Updated

Updated · Earth.com · Aug 9

Astronomers Photograph Betelgeuse B at 52 Milliarcseconds, Backing 2,200-Day Binary Theory

Q: With follow-up observations nearing in 2027, will Betelgeuse B finally solve the mystery of the supergiant's bizarre dimming?

Probably not by itself, but it could settle a major part of the puzzle. The December 2024 observations give the strongest evidence yet that Betelgeuse has a real companion: a faint blue-white star about 1,200 times dimmer than Betelgeuse, detected at 6.1 sigma and located where two 2024 studies predicted it should be. If follow-up imaging in spring 2027 finds the object again on the opposite side of Betelgeuse, astronomers will likely confirm that Betelgeuse B is truly in orbit and not a processing artifact or unrelated background source. That would be a big step because the companion offers a plausible explanation for part of Betelgeuse’s long roughly 2,200-day brightness cycle. Researchers think the smaller star may clear or heat dust near the red supergiant, changing how much of Betelgeuse’s light reaches Earth. But the team also says the effect appears too weak to explain all of the star’s variability. Betelgeuse still has its own pulsations, complex atmosphere and dust production, all of which likely contribute. So the 2027 observations are expected to answer the narrower question of whether Betelgeuse really is a binary system. They are less likely to fully solve the broader mystery of its bizarre dimming. Even if Betelgeuse B is confirmed, astronomers will still need to untangle how much of the dimming comes from the companion, how much from dust clouds, and how much from the supergiant’s own unstable outer layers.

3 articles · Updated · Earth.com · Aug 9

VLT images from December 2024 revealed a point source 1,200 times fainter than Betelgeuse at a 6.1-sigma signal, giving astronomers their clearest evidence yet of the long-suspected companion Betelgeuse B.
The find matches late-2024 predictions that a hidden partner drives Betelgeuse’s odd 2,200-day brightness cycle, after earlier Gemini observations saw only a tentative 1.5-sigma hint at the expected position.
Betelgeuse B appears to be a hot blue-white star 2.6 to 3.1 times the Sun’s mass, orbiting about 820 million miles from the red supergiant and passing through its dusty environment.
Dust clearing by the companion seems too weak to explain the full brightness swing, so the team argues the star likely perturbs Betelgeuse itself; a confirming sighting on the far side is planned for spring 2027.