Free Astronomy Magazine January-February 2025

JANUARY-FEBRUARY 2025 instruments, GRAVITY. After com- paring their new results with other previous observations of WOH G64, they were surprised to find that the star had become dimmer over the past decade. “We have found that the star has been experiencing a significant change in the last 10 years, provid- ing us with a rare opportunity to witness a star’s life in real time,” says Gerd Weigelt, an astronomy profes- sor at the Max Planck Institute for Radio Astronomy in Bonn, Germany and a co-author of the study. In their final life stages, red supergiants like WOH G64 shed their outer layers of gas and dust in a process that can last thousands of years. “This star is one of the most extreme of its kind, and any drastic change may bring it closer to an explosive end,” adds co- author Jacco van Loon, Keele Obser- vatory Director at Keele University, UK, who has been observing WOH G64 since the 1990s. The team thinks that these shed ma- terials may also be responsible for the dimming and for the unex- pected shape of the dust cocoon around the star. The new image shows that the cocoon is stretched- out, which surprised scientists, who expected a different shape based on previous observations and computer models. The team believes that the cocoon’s egg-like shape could be ex- plained by either the star’s shedding or by the influence of a yet-undis- covered companion star. As the star becomes fainter, taking other close-up pictures of it is be- coming increasingly difficult, even for the VLTI. Nonetheless, planned updates to the telescope’s instru- mentation, such as the future GRAV- ITY+, promise to change this soon. “Similar follow-up observations with ESO instruments will be important for understanding what is going on in the star,” concludes Ohnaka. T hanks to ESO’s Very Large Telescope Interferometer, astronomers have taken the first close-up picture of a star outside our galaxy, more than 160,000 light-years from us. The star is surrounded by a giant cocoon of dust, revealing it is in the last stages before becoming a supernova. This video sum- marises the discovery. [ESO] !