Ghostly in appearance,
is a remarkably simple, spherical nebula about
five light-years across.
Well within our own
Way galaxy, the cosmic
is roughly 7,000 light-years distant toward the constellation
Abell 39 is a planetary nebula, formed as a
once sun-like star's outer atmosphere was expelled
over a period of thousands of years.
Still visible, the nebula's central star
is evolving into a hot white dwarf.
Although faint, the nebula's simple geometry has
proven to be
exploring the chemical abundances and
life cycles of stars.
this deep image
recorded under dark night skies,
galaxies can be found --
some visible right through the nebula itself.