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WOH G64 is a system composed of a red supergiant (at left, in orange) and a smaller hot star (at right, in blue).
Astronomers using the Southern African Large Telescope (SALT) have solved a scientific mystery involving a red supergiant star that has been misbehaving.
“In the last decade, the star’s behaviour changed radically. It faded significantly, its pulsations suppressed,” said the South African Astronomical Observatory (SAAO) in a statement on Thursday.
In 2024, researchers had discovered that the red supergiant star named WOH G64 B had obtained a mysterious dust cloud in addition to its other strange behaviour.
Scientists turned to South Africa’s SALT telescope in Sutherland in the Northern Cape, to observe the star between November 2024 and December 2025. They discovered that WOH G64 B’s strange behaviour can be explained by its star twin and its powerful gravity, causing the red supergiant to expand its atmosphere to transform it into a new phase.
“We are essentially witnessing a ‘phoenix’ rising from the ashes,” explains Dr Jacco van Loon of Keele University in the UK who led the study. “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.”
