A team of astronomers has made a groundbreaking discovery by observing what they believe to be a never-before-seen companion star orbiting Betelgeuse, the pulsating red supergiant star in the Orion constellation. The companion star, colloquially called “Betelbuddy,” is estimated to have 1.5 times the mass of our sun and is visible due to its distinct blue hue.
Lead study author Steve Howell states that the speckle imaging technique used by his team revealed a young, bluish star not yet burning hydrogen at its core. The companion’s faintness is just one reason it’s been hard to spot, but the fact that it’s different in color from Betelgeuse allows astronomers to see it.
For decades, astronomers have observed Betelgeuse’s brightness fluctuating over a six-year cycle, and two independent groups suggested an unseen companion star could be causing this variability. However, previous attempts using the Hubble Space Telescope and Chandra X-Ray Observatory failed to detect such a star.
The new research uses speckle imaging to achieve high-resolution images of Betelgeuse and its companion. The team predicts that seeing the companion track along its proposed six-year orbit would represent a definitive detection of the companion.
According to the study, Betelgeuse wobbles toward and away from Earth due to the presence of a stellar companion. While questions remain about how exactly the companion is contributing to Betelgeuse’s variability, understanding this stellar pair can help astronomers understand pulsating red giant and supergiant stars in general.
However, the discovery also raises concerns about the fate of both stars. The companion star’s close orbit within the outer layers of Betelgeuse’s atmosphere will eventually lead to its doom, either through a slow drift closer or being destroyed in a supernova explosion.
Source: https://edition.cnn.com/2025/07/26/science/betelgeuse-star-stellar-companion