Planetary Nebulae

Other astronomical objects

Planetary nebulae are luminous clouds of gas that form at the end of the lifespan of a medium-sized star—for example, stars with an initial mass of about 1 to 8 solar masses. When a star has consumed its nuclear fuel, it expands into a red giant and ejects its outer layers into space. The exposed hot cores emit intense ultraviolet radiation, which ionizes the ejected gas and causes it to glow—thus creating the planetary nebula. The name comes from a time when these objects, due to their round shape, resembled planets in a telescope.

In summary:
  • Form at the end of the life of sun-like stars
  • Consist of a luminous gas cloud and a hot central star (white dwarf)
  • Visibility: several tens of thousands of years
  • Play an important role in the chemical evolution of the universe
  • Have nothing to do with planets; the name is historical

The Dumbbell Nebula Messier 27 is a mag 7.5 planetary nebula about 1300 light years distant in the constellation of the Fox. Formed about 10,000 years ago from the envelope ejected from a red giant star in its terminal phase, the nebula is expanding at a speed of about 30 km/s. The core of the giant star remained in the center of the nebula as a white dwarf with a temperature of over 100,000 Kelvin and a magnitude of 14.
The Ring Nebula Messier 57 is a planetary nebula in the constellation Lyra.
Abell 39, the 39th entry in the catalog of large nebulae discovered by George Abell in 1966, is a beautiful example of a planetary nebula.
Top right: Planetary nebulae "Owl Nebula, Messier 97" and Botton left: "Surfboard Galaxy Messier 108"
Reflection- and Dark NebulaeGalaxies and Galaxy groups