User:JeffKo427/sandbox/SCN

The Southern Crab Nebula is a plantetary nebula located in the constellation Centaurus. It is significant as a symbiotic star, consisting of a white dwarf and a red giant orbiting around eachother.

History
The nebula was first discovered in 1989. Theories about the possible link between symbiotic star systems and planetary nebulae (see below) in November of that year by Julie Lutz, of Washington State University.

Astronomical Activity
Pictures taken by the Hubble Space Telescope in 1999 show that the nebula actually consists of two different nebulae, one inside the other. Each nebula was formed by the red giant, which is also a Mira variable, releasing stellar matter. This matter is then captured by the white dwarf's gravitational pull, and orbits around the star until being pulled to the surface. When enough gas builds up, it sparks an explosion, which releases the gas clouds that make up each nebula. This has occured twice in the nebula's history. The nebula, according to one theory, represents a link between symbiotic star systems and planetary nebulae.