At a dizzying distance of 160,000 light years, a giant star named WOH G64 reveals the mysteries of its final moments before a spectacular supernova explosion. Located in the Large Magellanic Cloud, a satellite galaxy of the Milky Way, this red supergiant approximately 2,000 times the size of the Sun was captured by the European Southern Observatory (ESO). This advance marks an important step in observing stars beyond our galaxy.
A unique look at a dying star
This is a world first. Astronomers have managed to observe in detail a star in another galaxy on the verge of exploding in a supernova. Woh g64a red supergiant whose size is 2,000 times greater than that of the Sunis surrounded by a thick cocoon of gas and dust which it expels at high speed. Red supergiants, massive stars at the end of their lives, slowly shed their outer layers of gas and dust, a process that can last thousands of years. This phenomenon was captured in detail using the Large Telescope Interferometer (VLTI) of the European Southern Observatory (ESO).
One detail particularly surprised the researchers: the dust cocoon which surrounds the star has a elongated shape similar to an egg. However, this structure is unusual and does not correspond to current computer models. Scientists consider several explanations, including the hypothesis that a invisible companion star could influence the shape of the cocoon.
Another unexpected observation: the star has lost brightness over the last ten years. It's a rare behavior that intrigues researchers because it offers a unique opportunity to study the final stages of a star's life. “ Each observation brings us an additional piece to the puzzle “, explains Jacco van Loon, director of the Keele Observatory in the United Kingdom. He has been studying woh g64 since the 1990s. For him, these discoveries show how complex and unpredictable massive stars can be.
What this means for the future
Observing such a distant star is a technical feat. Still, woh g64 is getting weaker and weaker, complicating future observations. Researchers are therefore counting on new instruments, such as gravity+to continue studying this star and others in distant galaxies.
Thanks to these new observations, however, woh g64 is no longer just a distant star. It becomes a fascinating object of study which allows us to better understand the final stages of life of giant stars. This work is therefore essential to better understand the mechanisms that lead to supernova explosions. However, these cosmic phenomena play a key role in the formation of chemical elements and the birth of new stars.
