Object Analysis

The Gum Nebula (Gum 12) is an immense emission nebula that spans about 40 degrees across the constellations Vela and Puppis. It is located roughly 1,470 light-years away. Because it is so vast and faint, it was only identified in the 1950s by Australian astronomer Colin Gum using wide-field photography.

The origin of the Gum Nebula is a subject of ongoing research. Most astronomers believe it is a "Strömgren sphere"—a shell of ionized gas—but one that has been greatly expanded by multiple supernova explosions, including the one that created the Vela Supernova Remnant which sits inside it. It acts as a giant bubble of hot gas in the Milky Way's disk.

Because it is so close to Earth, we are actually looking at it from the inside of its outer shell in some directions. It contains many smaller, more famous objects, including the Pencil Nebula and the Vela Pulsar. It is a spectacular example of how multiple generations of stars can sculpt the interstellar medium on a gargantuan scale.