WOH G64 becomes hotter and changes from red to yellow
Updated
Updated · Sky at Night Magazine · May 5
WOH G64 becomes hotter and changes from red to yellow
9 articles · Updated · Sky at Night Magazine · May 5
Nature Astronomy researchers said the giant binary system in the Large Magellanic Cloud heated by more than 1,000°C after tracking over 30 years of brightness data.
The star dimmed in 2011, then reheated and brightened, before another major fading event in 2025, behaviour astronomers say is unprecedented for a red supergiant on human timescales.
Scientists say the changes may mark WOH G64's final life stages before a supernova, offering a rare real-time view of how massive stars die or collapse into black holes.
Is a giant star truly dying, or is its hidden companion creating a cosmic masquerade?
A star is changing color before our eyes. What does its death reveal about the elements that created us?
WOH G64’s Dramatic Evolution: Unraveling the Red Supergiant to Yellow Hypergiant Metamorphosis
Overview
Between 2011 and 2014, the massive star WOH G64 underwent a dramatic transformation from a red supergiant to a yellow hypergiant, marked by a sharp dimming, a temperature increase of about 1,000 K, and a contraction to roughly half its original size. This change was accompanied by the disappearance of titanium oxide absorption bands and the emergence of emission lines, alongside a shift from semi-regular to irregular brightness variability. Two main explanations involve its binary companion: one where the red supergiant engulfed the companion, triggering mass ejection and exposing hotter layers, and another where tidal forces during the companion's close approach temporarily distorted the star's atmosphere, mimicking this transformation. The star’s future remains uncertain, highlighting the crucial role of binary interactions in massive star evolution.