Bubble nebulae in NGC 6822
author: Anglo-Australian Observatory/David Malin Images/Novapix
reference: a-neb82-00001
Image Size 300 DPI: 51 * 40 cm
NGC 6822 is a nearby irregular galaxy reminiscent of the Large Magellanic Cloud (LMC). Like the LMC it contains many, extremely hot stars of the Wolf-Rayet type, stars which often have intense stellar winds blasting from their surfaces. Small groups of such stars are found at the centres of the bubble nebulae seen here, which are are the result of the stellar winds colliding with the more or less stationary interstellar medium in NGC 6822. At the interface of the collision, the interstellar medium glows, producing a thin, luminous bubble. Such bubbles are rare in the more turbulent Milky Way galaxy, but Henize 70 in the Large Magellanic Cloud is similar.