NGC 6543, nicknamed the `Cat's Eye', is one of the most complex planetary nebulae ever seen. It is about 3,000 light years away in the constellation Draco. This HST image reveals concentric shells of gas, high-speed jets and unusual knots of gas. Estimated to be 1,000 years old, the nebula represents a late stage in the evolution of a dying star. The term `planetary nebula' is a misnomer. Planetary nebulae have nothing to do with planets except that the 18th century observer, Sir William Herschel, thought their appearance in his telescope reminiscent of his views of the planets.
The intricate structures within NGC 6543 are more complicated than normally seen in planetary nebulae and may be explained if there is a double star system at its center. The two stars would be too close to be resolved separately and appear as a single point of light.
A fast stellar wind blowing off one of the central stars created the elongated shell of dense glowing gas. This structure is embedded inside two larger lobes of gas blown off the star earlier. These lobes are pinched by a ring of denser gas, thought to have been ejected in the plane of the orbits the stars follow around each other. The suspected companion might also be responsible for the pair of high-speed jets at right angles to the ring.
Camera: WFPC2
Technical Information: Composite of three images taken in three different colors. Red represents light from hydrogen, blue from neutral oxygen and green from ionized nitrogen.
Credit: J. P. Harrington and K. J. Borkowski (University of Maryland), and NASA
