A giant bubble blown by the massive Wolf-Rayet star HD 50896, the purple star in the centre of the image. X-ray data from XMM-Newton’s EPIC camera are shown in blue, while optical images were acquired using the Michigan Curtis Schmidt Telescope at Cerro Tololo Inter-American Observatory (CTIO) and presented in red (H-alpha) and
Canis Major, S308 is a colossal bubble, almost 60 light-years across, blown by the powerful stellar wind of the WR star HD 50896. The stellar wind itself is shock-heated to high temperatures and emits X-rays, whereas the nebular material seen in H-alpha is snow-plowed by the stellar wind and a shock propagating outwards into the circumstellar medium is seen in the [O III] light. This bubble will soon break and disperse into the circumstellar medium. The WR star will end its life later in a supernova explosion.