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
18/05/1998

Why isn't the star in the center of the nebula? NGC 6369 appears to be a fairly ordinary planetary nebula. It can be seen with a good telescope in the constellation of Ophiuchus. The gas expelled by the central star is bunched in the shape of a donut or cylinder. During the planetary nebula phase, the central star sheds its outer atmosphere as it is evolving to become a white dwarf star. The above image was taken with the Hubble Space Telescope. A closer look at NGC 6369 indicates that the central star is closer to a dimmer edge of the nebula than to the opposing brighter edge.