NGC 6369: The Little Ghost Nebula
This pretty planetary nebula, cataloged as NGC 6369, was discovered by 18th
century astronomer William Herschel as he used a telescope to explore the
medicinal constellation Ophiucus. Round and planet-shaped, the nebula is also
relatively faint and has acquired the popular moniker of Little Ghost Nebula.
Planetary nebulae in general are not at all related to planets, but instead are
created at the end of a sun-like star's life as its outer layers expand into space
while the star's core shrinks to become a white dwarf. The transformed white dwarf
star, seen near the center, radiates strongly at ultraviolet wavelengths and powers
the expanding nebula's glow. Surprisingly complex details and structures of NGC 6369
are revealed in this delightful color image composed from Hubble Space Telescope data.
The nebula's main ring structure is about a light-year across and the glow from ionized
oxygen, hydrogen, and nitrogen atoms are colored blue, green, and red respectively. Over
2,000 light-years away, the Little Ghost Nebula offers a glimpse of the fate of our Sun,
which should produce its own pretty planetary nebula only about 5 billion years from now.