This nebular region consists of the cast-off outer atmosphere of an aging star. It is roughly elliptical in shape with several clumps of ionized material, and is surrounded by a larger region of low-level emission that extends for three times the nominal diameter of the main nebula.[3] The nebula is expanding with an average velocity of 12.5 km/s. It consists of two shells: the inner shell is elliptical and measures 11″ × 6″, while the more rapidly expanding outer shell is rounder with a diameter of 15″. The inner shell has what appears to be multiple bubble-like shapes. The clumps in the outer shell may be the result of instabilities.[8]
The elemental abundances of the nebula are very similar to those in the Sun, except for a times two enrichment of nitrogen. The latter suggests that the central star did not go through second dredge-up. The central star has an apparent visual magnitude of 13.43. It shines with 830 times the luminosity of the Sun and has 22.7% of the Sun's radius.[3] It is displaced slightly from the center of symmetry for the nebula.[8]
^Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. Vol. 2. Sky Publishing Corporation and the European Space Agency. p. 948. ISBN0-933346-83-2.