One of the largest known stars in the Universe may be entering the final stages of its life, with astronomers reporting dramatic and unusually rapid changes that could signal an eventual supernova.
Research published in the journal Nature Astronomy shows how WOH G64, a giant binary star system in the Large Magellanic Cloud, has recently undergone a striking transformation.
In 2024, astronomers revealed an image of WOH G64, making it the first ever close-up image captured of a star beyond our Galaxy.
More amazing Chandra observations
Now, researchers say they've examined more than 30 years of brightness measurements and found that the star, long classified as a cold, red supergiant, has become markedly hotter – by over 1,000°C – and now appears yellow rather than red.
The strange dimming of WOH G64
The star first dimmed in 2011, then rapidly reheated and brightened, followed by another significant fading event in 2025.
Such behaviour has never been observed in a star of this size and type on human timescales.
Red supergiants, which can grow to more than 1,500 times the size of the Sun, do shed material as they approach the end of their lives.
These events shape whether a star ultimately explodes as a supernova or collapses into a black hole.
But WOH G64’s extreme transition offers a rare opportunity to witness stellar transformations in real time.
The evolution of massive stars typically unfolds over millions or billions of years, not within a few years of observation, making this case especially scientifically valuable.
By continuing to monitor this object, researchers hope to refine their understanding of how the Universe’s most massive stars live, evolve and die – processes that ultimately seed the cosmos with heavy elements, enabling the formation of planets and, eventually, the building blocks of life.
