THE RISE OF A ZOMBIE NEBULA
Feast your eyes on this gorgeous planetary nebula that has been "re-animated."
Abell 30, as astronomers call it, glows in X-ray light (shown in purple) and optical (green, blue, and orange). How did such a complex nebula form?
A planetary nebula signals the quiet death of a star that is not large enough to produce a supernova. Instead, as the star's core runs out of hydrogen for nuclear fusion, the outer layers puff up and cool down, making the star a red giant. Strong stellar winds blow material from the outer layers into a shell or some other strange shape, such as an hourglass. The stellar core becomes a hot white dwarf star, giving off plenty of ultraviolet radiation that causes the surrounding gas to glow.
But sometimes, the dead star doesn't quite stay dead.
In a "born again" planetary nebula, as described in the literature as early as 1983, nuclear fusion reignites some of the helium in the white dwarf star, making carbon and oxygen and creating a new phase of stellar winds.
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Abell 30 is one of this rare class of "born-again" planetary nebulae, but I do hope the name "zombie nebula" catches on with further investigations.
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