The 3-D ionization structure and evolution of NGC 7009 (Saturn Nebula)
The 3-D ionization structure and evolution of NGC 7009 (Saturn Nebula)
Tomographic and 3-D analyses for extended, emission-line objects are applied to long-slit ESO NTT + EMMI high-resolution spectra of the intriguing planetary nebula NGC 7009, covered at twelve position angles. We derive the gas expansion law, the diagnostics and ionic radial profiles, the distance and the central star parameters, the …