Atomic data and the density structures of planetary nebulae

Abstract

We study the density structures of planetary nebulae implied by four diagnostics that sample different regions within the nebulae: [S II] $\lambda 6716/\lambda 6731$, [O II] $\lambda 3726/\lambda 3729$, [Cl III] $\lambda 5518/\lambda 5538$, and [Ar IV] $\lambda 4711/\lambda 4740$. We use a sample of 46 objects with deep spectra that allow the calculation of the electron density from these four diagnostics, and explore the impact that different atomic data have on the results. We compare the observational results with those obtained from photoionization models characterized by three different density structures. We conclude that the atomic data used in the calculations of electron density fully determine the density structures that are derived for the objects. We illustrate this by selecting three combinations of atomic data that lead to observational results that are compatible with each of the three different density structures explored with the models.

9 pages, 6 figures, 2 table. Accepted for publication in MNRAS

References in corpus (5)

• PyNeb: a new tool for analyzing emission lines. I. Code description and validation of results
• Elemental abundances of Galactic bulge planetary nebulae from optical recombination lines
• Oxygen enrichment in carbon-rich planetary nebulae
• Faint recombination lines in Galactic PNe with [WC] nucleus
• C/O ratios in planetary nebulae with dual-dust chemistry from faint optical recombination lines