The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major Axis

Abstract We derived position–velocity density distribution diagrams along the major (PA = 77°) axis of elliptical planetary nebula NGC 7009 with Keck HIRES [S ii ] 6716/6731 Å doublet spectral images. The average densities main shell and knots from fluxes integrated over line sight indicate a range N e 10 3.4 to 3.9 cm −3 , while local volume fraction resolved in radial velocities show considerably large about 2.8 –10 4.7 . projection angle is ψ ∼ 18.3° (±2°). Assuming that an ellipsoidal ≃ 16″ b 6″, we found expansion velocity, radius, latitude four hot bubble. at points symmetrical positions are roughly aligned same latitudes ϕ ±34.5° (±0.6°): one pair expands 35 km s −1 close shell, other rapidly 60 distance r 16″. In 65°–75°, bubble relatively structure velocity 130–150 points, which expand faster than appear have been formed by two three eruptions different epoch primary formation.