A Reexamination of Electron Density Diagnostics for Ionized Gaseous Nebulae

Abstract

Abstract. We present a comparison of electron densities derived from optical forbidden line diagnostic ratios for a sample of over a hundred nebulae. We consider four density indicators, theand [Ar ] λ4711/λ4740 doublet ratios. Except for a few H  regions for which data from the literature were used, diagnostic line ratios were derived from our own high quality spectra. For the [O ] λ3729/λ3726 doublet ratio, we find that our default atomic data set, consisting of transition probabilities from Zeippen (1982)

Evolution of Planetary Nebulae with WR-type Central Stars

“…We find N/O = 0.19, in generally good agreement with Aller& Keyes (1987),Peña et al (2001) andHenry et al (2004). A density of N e = 6500 cm −3 was derived from the [S II] µ6731/λ 6717 flux ratio, which is almost the same as the value found byKwitter et al (2003) andWang et al (2004).NGC 6629 ( = PN G009.4−05.0). Our abundance analysis presents N/O = 0.09 and He/H = 0.095, in good agreement with the most values from the literature, as listed in Table 3.11.…”