NGC 6153: a super-metal-rich planetary nebula?

• DOI: 10.1046/j.1365-8711.2000.03167.x
• Publication Date: 2003-03-12T12:59:10Z
• Authors: X.- W. Liu; P. J. Storey; M. J. Barlow; I. J. Danziger; M. Cohen; M. Bryce
• Keywords: Line (geometry); Orion Nebula; Forbidden mechanism; Excitation temperature

We have obtained deep optical spectra of the planetary nebula NGC 6153, both along its minor axis and by uniformly scanning a long slit across whole nebula. The scanned spectra, when combined with nebular total Hβ flux, yield integrated fluxes for all lines (∼400) in our which are rich strong recombination from C, N, O Ne ions. A weak viλ3811 emission line central star has been detected, suggesting that nucleus 6153 hydrogen-deficient surface. data, together ISO LWS 43–197 μm spectrum archival IUE IRAS LRS used to study thermal density structure derive heavy-element abundances produced different excitation mechanisms. In cases, C2+/H+, N2+/H+, O2+/H+ Ne2+/H+ derived multiple (ORLs) consistently higher, about factor 10, than corresponding values deduced optical, UV or infrared (IR) collisionally excited (CELs), regardless energies critical densities latter. agreement between temperature-sensitive forbidden temperature-insensitive IR fine-structure rules out temperature fluctuations as cause large difference ORL CEL abundances.