The observed glow of the central star is so energetic that it causes the previously expelled gases to brightly fluoresce.

[5] The Helix Nebula is thought to be shaped like a prolate spheroid with strong density concentrations toward the filled disk along the equatorial plane, whose major axis is inclined about 21° to 37° from our vantage point.

The outer-most ring appears flattened on one side due to it colliding with the ambient interstellar medium.

[13] These knots are radially symmetric (from the CS) and are described as "cometary", each centered on a core of neutral molecular gas and containing bright local photoionization fronts or cusps towards the central star and tails away from it.

The low density, high expansion velocity ionized inner nebula is accelerating the denser, slowly expanding, largely neutral material which had been shed earlier when the star was on the Asymptotic Giant Branch.

[1] The star has a radius of 0.025 solar radii (17,000 km), a mass of 0.678 M☉, a temperature of 120,000 Kelvin and has an apparent magnitude of 13.5.