In 2014, WOH G64, one of the largest stars known in the universe, began a fascinating transformation. Research led by Gonzalo Muñoz-Sanchez from the National Observatory of Athens explored how this enormous star shifted from a red supergiant to a rare yellow hypergiant, hinting that it could be on the brink of a supernova explosion. This change offers a rare opportunity to witness a massive star shedding its outer layers and moving towards the end of its life.
WOH G64 was first spotted in the 1970s while observing the Large Magellanic Cloud, a dwarf galaxy near our Milky Way. It stands out not only for its brightness but also for its colossal size—over 1,500 times the radius of our Sun. In 2024, it became the first star outside our galaxy to be photographed in detail, thanks to the Very Large Telescope Interferometer. This image revealed a dusty cocoon enveloping the star, indicating it is losing mass as it ages.
At less than 5 million years old, WOH G64 is quite young in cosmic terms, especially compared to our Sun, which is about 4.6 billion years old. Massive stars like WOH G64 burn fast and bright, rapidly consuming their nuclear fuel. Initially, they burn hydrogen before evolving into red supergiants. Some may then transform into hypergiants. The process involves a quick transition where they shed outer layers and shrink, a change that usually signals their impending demise in a spectacular supernova explosion.
So, what triggered this change in WOH G64? The recent study theorizes that a significant portion of the star’s surface was ejected, possibly due to interactions with a companion star. This has been supported by light spectrum analysis. Another possibility is that WOH G64 is entering a phase known as the “superwind.” This stage might occur as the star’s core experiences strong pulsations while its fuel runs low.
Understanding these transitions is critical. According to astrophysicists, WOH G64 could provide valuable insights into stellar evolution and the life cycles of massive stars. In fact, researchers are closely monitoring the star, hoping to witness its death. Historically, seeing a star’s final moments is rare. As technology improves, scientists can now capture these events more effectively, making it an exciting time for astronomy.
In conclusion, the journey of WOH G64 reflects the dynamic and ever-changing nature of our universe. If we’re fortunate, we may witness its spectacular end, adding to our knowledge of these magnificent cosmic giants.
