A mysterious ‘superbubble’ carved in the heart of a glowing emission nebula

N44, a 1,000-lightyear-wide emission nebula in the Large Magellanic Cloud, features an intriguing void, or superbubble, where hydrogen gas and dust has been blown away. The void, some 250 light years across, is obvious in this recent Hubble Space Telescope image, but what caused it is a matter of debate. Stellar winds from massive stars in the bubble’s interior may be responsible but that scenario is not supported by measured wind velocities. Another possibility: supernova explosions and expanding shells of debris that may have pushed material outward. At least one supernova remnant has been found near the void and other evidence points to multiple, chain-reaction star forming events. The deep blue area at the upper right of the superbubble is a region of intense star formation and is one of the hottest areas in the nebula.

N44, as seen by the Hubble Space Telescope. Click twice twice for a larger view. Image: NASA, ESA, V. Ksoll and D. Gouliermis (Universität Heidelberg), et al.; Processing: Gladys Kober (NASA/Catholic University of America)