New Observations Confirm WOH G64 Remains a Red Supergiant
Recent studies reveal that WOH G64, previously thought to be transitioning into a yellow hypergiant, continues to exist as a red supergiant, with its unusual behavior likely due to interaction with a companion star.
Recent observations have confirmed that WOH G64, a massive star located approximately 163,000 light-years away in the Large Magellanic Cloud, remains a red supergiant. This finding challenges previous assumptions that the star was transitioning into a yellow hypergiant, a phase often preceding a supernova explosion.
Between November 2024 and December 2025, researchers utilized the Southern African Large Telescope (SALT) to collect spectral data from WOH G64. The presence of titanium oxide in the star's atmosphere, a molecule typically found in red supergiants, indicates that WOH G64 has not undergone the anticipated transformation. Dr. Jacco van Loon, an astrophysicist at Keele University and co-lead author of the study, stated,
"This implies that WOH G64 is currently a red supergiant and may never have ceased to be."
The study suggests that the star's unusual behavior may be attributed to the presence of a smaller companion star. The gravitational interaction between the two stars could be causing the outer layers of WOH G64 to stretch, leading to the observed changes. Dr. van Loon further explained,
"The atmosphere of the red supergiant is being stretched out by the approach of the companion star, but it has not been stripped altogether. It persists."
These findings provide new insights into the behavior of massive stars and the complex interactions within binary systems. The research has been published in the Monthly Notices of the Royal Astronomical Society.