Astronomers Observe Unprecedented Changes in Massive Star WOH G64

WOH G64, a massive star located approximately 163,000 light-years away in the Large Magellanic Cloud, has recently exhibited significant changes, leading to debates among astronomers regarding its evolutionary status and future.

Initially classified as a red supergiant, WOH G64 is about 1,540 times the size of the Sun and has been a subject of study since the 1970s. In 2014, observations indicated a shift in the star's color and an increase in surface temperature, suggesting a transition to a yellow hypergiant phase. This transformation was interpreted as a potential precursor to a supernova event.

However, subsequent studies have challenged this interpretation. Between November 2024 and December 2025, researchers using the Southern African Large Telescope (SALT) detected molecular absorption bands of titanium oxide in WOH G64's atmosphere, a characteristic feature of red supergiants. This finding implies that the star remains in its red supergiant phase.

The presence of a companion star has been proposed as a factor influencing WOH G64's behavior. Interactions between the two stars may have led to mass loss and the formation of a dust cloud, affecting the star's appearance and spectral characteristics.

The future of WOH G64 remains uncertain. While some scenarios suggest an imminent supernova explosion, others propose a direct collapse into a black hole or further evolutionary changes influenced by its binary companion. Continued monitoring is essential to understand the processes governing the final stages of massive stars.