A Star the Size of 1,500 Suns Went from Red to Yellow

A star so enormous it would swallow everything in our solar system out to Jupiter has spent the last decade quietly changing colors. Known as WOH G64, it has astronomers' full attention. The news is not good.

WOH G64 sits in the Large Magellanic Cloud, a dwarf galaxy about 163,000 light-years away. At roughly 1,540 times the radius of the Sun, with 30 times its mass and 282,000 times its brightness, the star had been classified as a red supergiant since its discovery in the 1970s.

Around 2014, something shifted. Its surface temperature climbed by more than 1,000 degrees Celsius, its color turned from red to yellow, and the star shrank from 1,500 solar radii to roughly 800. A paper published in Nature Astronomy in February 2026 argues it has become a yellow hypergiant, one of the rarest stellar classifications, representing a brief transitional phase before supernova. The star is actively shedding its outer layers, and on stellar timescales, an imminent supernova could still be hundreds to thousands of years away.

There is a complication. Between November 2024 and December 2025, two astronomers using the Southern African Large Telescope detected titanium oxide in the star's atmosphere. A yellow hypergiant runs too hot to sustain that molecule. Their conclusion: the star may still be a red supergiant and may never have stopped being one.

Both scenarios, researchers note, are exceptionally rare. Witnessing either unfold on human timescales is almost without precedent. Nobody knows exactly what WOH G64 is doing. But something is happening 163,000 light-years away, and we have front-row seats.

Read the full story at IFLScience, July 16, 2026

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