All Tables

Table 1: Journal of observations.
Table 2: Dereddened fluxes of the lines and doublets used in this work, in units of H $\beta =100$ , and associated measure standard deviations in the same units. ^a Fluxes corrected for the SWS apertures.
Table 3: Empirical temperatures derived from five line ratios.
Table 4: Empirical abundance ratios of various elements, with the ICFs specified.
Table 5: Observational values of the line ratios used to constrain the photoionization models and model results in the form (model-observation)/(tolerance). The models are: [FS] Full Sphere; [HB] Hollow Bubble; [DD1] and [DD2] H $\beta$ constrained Density Distribution, 4.2 Myr spectrum; [DD2] H $\beta$ constrained Density Distribution, 3.6 Myr Spectrum; [DF] Density Fluctuations; [DG] Dust Grains. The geometric corrections for the models of Sect. 6 and further sections are also written. ^a Values are valid for the whole nebula; the other data are representative of the optical slit.
Table 6: Parameters of the model density distribution, fitted on the slit H $\beta$ profile and on the image. The distances are expressed in 10²⁰ cm, and the densities in cm^-3. ^a Projected minor and major semi-axes. ^b Projected distance to the source.
Table 7: Some spectral properties of the three zones N, SW and SE and of the whole cluster, assuming an age of 3.6 Myr. $Q_{\rm tot}({\rm H}^0)$ is the total photon luminosity of the cluster in the Lyman continuum range.
Table 8: Empirical temperatures yielded by the spectra of the zones N, SW and SE and of the whole cluster.
Table 9: O⁺⁺/H⁺ and Ne⁺⁺/O⁺⁺ abundance ratios derived from different diagnostics. The error bars include the uncertainties related to the temperature diagnostics and to the [O III]/H $\beta$ and [Ne III]/[O III] line ratios that we used.