NGC 3242 (also known as the Ghost of Jupiter
or Caldwell 59) is a planetary nebula located in the
constellation Hydra. When stars with a mass similar to our sun
approach the end of their lives by exhausting supplies of
hydrogen and helium fuel in their cores, they swell up into cool
red-giant stars. In a last gasp before death, they expel the
layers of gas in their outer atmosphere. This exposes the core
of the dying star, a dense hot ball of carbon and oxygen called
a white dwarf. The white dwarf is so hot that it shines very
brightly in the ultraviolet. The ultraviolet light from the
white dwarf, in turn, ionizes the gaseous material expelled by
the star causing it to glow. A planetary nebula is really the
death of a low-mass star.
