Planetary Nebula
An expanding shell of ionized gas ejected from a red giant star in the late stages of stellar evolution. Despite the name, it has no connection to planets. The glowing gas is illuminated by the hot core of the dying star.
Source: science.nasa.gov
APODs including "Planetary Nebula"
NGC 3242: The 'Ghost of Jupiter' Planetary Nebula Credit:
31/03/1997
It's a weed, it's Jupiter, no it's - actually planetary nebula NGC 3242. After a star like our Sun completes fusion in its core, it throws off its outer layers it a striking display called a planetary nebula. NGC 3242 is such a planetary nebula, with the stellar remnant white dwarf star visible at the center. This nebula is sometimes called "The Ghost of Jupiter" for its similar appearance to the familiar planet. NGC 3242 is much farther away however, than the measly 40 light-minutes distance to Jupiter. In fact, by comparing the apparent expansion rate with the actual rate determined from Doppler studies, astronomers have estimated the distance to NGC 3242 to be about 1400 light-years away. The red FLIERs visible near the edges of the nebula remain mysterious.