Free Astronomy Magazine September-October 2025

10 SEPTEMBER-OCTOBER 2025 ASTRO PUBLISHING I n the background, an artist's impres- sion of the supernova remnant SNR 0509-67.5. Observations from the Very Large Telescope have shown that it is the expanding remains of a dead star that exploded twice hundreds of years ago. [ESO/M. Kornmesser] stronomers have found the first visual evidence that a star has died by detonating twice. Observations taken with ESO’s Very Large Telescope (VLT) revealed concentric shells of calcium in the supernova remnant SNR 0509-67.5. These features indicate that the now-dead star exploded with two detonations. This video summarizes the discovery. [ESO]