Astr112 Photography Projects, Fall 2007

NGC 7008, Eric Thayer

NGC 7008 is a planetary nebula. A planetary nebula is formed when a star ranging anywhere from 0.08 to 8 times the mass of the sun reaches the end of its life.  The star runs out of hydrogen fuel to burn and expands into a red giant. It ejects its outer layers, leaving behind its carbon and oxygen core. The ejected material forms a nebula, while the core becomes a white dwarf.  NGC 7008 is one such nebula, found in the constellation Cygnus.  Its magnitude is about 13.3, which is exceptionally bright for an object this small. The distance to this nebula is still unknown.

The bright star at the center is the white dwarf leftover from the formation of the nebula.  The green and purple rings surrounding it are what used to be the outer layers of the star. The outer layers of material are reflecting the light that the center star gives off. Its deep purple color is rare in space objects.  The two stars near its north end are orbiting each other in a double star formation.  The actual distance to NGC 7008 is unknown, but if we assume that it’s about 1000 light-years, then the nebula itself would be about one half of a light-year across.

References:

Solomon, Jim. "SaratogaSkies: Jim Solomon's Astropics." http://www.saratogaskies.com/image.pl?i=132

Welch, Kevin. "Students for the Exploration and Development of Space." http://seds.org/~spider/ngc/ngc.cgi?7008