One of the largest known stars in the Universe, WOH G64, is undergoing a violent transformation. According to new research published in 'Nature Astronomy', the object located in the Large Magellanic Cloud has transitioned from a red supergiant phase to a rare yellow hypergiant, intensely shedding its outer material. This process, observed over just a few years, is interpreted by astronomers as preparation for a final supernova explosion. An international team of scientists, including Polish researchers from the Astronomical Observatory of the University of Warsaw, is monitoring these changes, which provide unprecedented data on the final stages of the most massive stars' lives.

Rapid change in star type

Research has shown that in just a few years, WOH G64 evolved from a red supergiant to a yellow hypergiant. This transformation, whose turning point was observed around 2014, is associated with significant heating of the object and intense shedding of its outer layers of material into space.

Preparations for the end of life

The observed phenomena – rapid mass loss and change of state – are interpreted by scientists as a countdown to the star's inevitable end of life. The final stage for such a massive object is likely to be a spectacular supernova explosion, although a collapse without a visible explosion is also possible.

Giant size and young age

WOH G64 is a cosmic colossus with a radius over 1,500 times that of the Sun. Despite its gigantic size, it is a relatively young object, less than 5 million years old, while the Sun has existed for over 4.6 billion years.

International research with Polish participation

The key discovery is the result of work by an international team led by Gonzalo Muñoz-Sanchez from the National Observatory of Athens. Polish astronomers from the University of Warsaw, members of the OGLE project team, also participated in the research.

Astronomers are observing in real-time a dramatic countdown to a potential cosmic catastrophe. The giant star WOH G64, located in the neighboring galaxy of the Large Magellanic Cloud, is undergoing a rapid and violent transformation that scientists believe heralds its imminent end. The latest research, published in the prestigious journal 'Nature Astronomy', indicates that the object transitioned in just a few years from the red supergiant phase to a rare yellow hypergiant. This transition, observed particularly clearly around 2014, indicates the star is heating up and intensely shedding its outer layers of material into space. According to scientists led by Gonzalo Muñoz-Sanchez from the National Observatory of Athens, this process is a clear signal that the massive star is preparing for the final act of its short life. For an object of WOH G64's mass, this most likely means an explosion of a supernova on an unimaginable scale, although a scenario of a quiet collapse into a black hole also remains possible. The phenomenon is all the more valuable to science because it concerns a star with nearly record-breaking parameters. Its radius, exceeding 1,500 solar radii, makes it one of the largest known celestial bodies. Paradoxically, from an evolutionary perspective, this cosmic colossus is an infant – it is estimated to have ignited just five million years ago. Studying the final stages of massive stars' lives is a key challenge of modern astrophysics. Theory predicts that stars significantly more massive than the Sun end their lives in spectacular supernova explosions, which scatter heavy elements essential for planet and life formation throughout the cosmos. However, direct observations of these processes are extremely rare due to their short duration on a cosmic scale. Polish astronomers from the Astronomical Observatory of the University of Warsaw, part of the OGLE project team, participated in the groundbreaking observations. Their contribution highlights the role of Polish science in global space research. Importantly, WOH G64 was the first star outside the Milky Way to be photographed in detail as early as 2024, thanks to the Very Large Telescope Interferometer. Further monitoring of WOH G64 will provide invaluable data, allowing verification of theoretical models and a better understanding of the final moments of the largest stars in the Universe. These observations are being conducted from a safe distance for Earth of about 160,000 light-years.

Mentioned People

  • Gonzalo Muñoz-Sanchez — Scientist from the National Observatory of Athens, leading the research on WOH G64