2018/07/04 by D. Barría, Daniela Barria, S. Kimeswenger +1 · 8 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics #Astrophysics and Star Formation Studies #Collisional excitation #Doubly ionized oxygen #Excitation #Ion #Ionization #Line (geometry) #Line-of-sight #Physics #Planetary nebula #Shell (structure) #Stars #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1093/mnras/sty1796
published in Monthly Notices of the Royal Astronomical Society 480(2), 1626-1638 (Oxford University Press) · 14 pages, 11 figures, 2 tables, accepted for publication in Monthly Notices of the Royal Astronomical Society
arxiv created 2018/07/04 · openalex publication_date 2018/07/04 · arxiv updated 2018/07/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We performed a detailed photometric analysis and photoionization modelling on three high-excitation multiple-shell planetary nebulae: NGC 3242, NGC 6826, and NGC 7662. Archival Hubble Space Telescope/Wide Field Planetary Camera 2 (HST/WFPC2) narrow band filter images were used to investigate shocked regions by two independent methods: using low-excitation ions (via H α/[N ii] versus H α/[S ii] extended diagnostic diagrams) and by means of high-excitation species looking for regions of enhanced [O iii]/H α line ratios. Shocked region analysis via low-excitation ions shows that major deviations from the general inside to outside ionization trend correspond only to regions where fast low-ionization emission regions or low-ionization emission line structures are located. The reduction on the signal-to-noise ratio at the outskirts of the [O iii]/H α ratio maps made us unable to unambiguously identified for an enhancement on the [O iii]/H α line ratio as an indicator for shocks. For non-shocked regions, we performed a photoionization modelling using cloudy. Fittings to the [O iii]- and H α-observed radial profiles lead us to constrain on the free parameters of the density laws and filling factors together to temperatures and luminosities for the CSPNe. Best-fitting models show a very well representation of the [O iii] and H α emission. Discrepancies in the model fittings to the [N ii] and [S ii] profiles at NGC 6826 and NGC 3242 can be attributed in the former case, due to a contamination by the light of the CSPN and, in the latter case, either due to gas inhomogeneities within the clumps or to a leaking of ultraviolet radiation.