Imaging spectrophotometry of the planetary nebula NGC 6720 (the Ring Nebula)

Abstract

view Abstract Citations (25) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Imaging Spectrophotometry of the Planetary Nebula NGC 6720 (The Ring Nebula) Lame, N. J. ; Pogge, R. W. Abstract Detailed emission-line imaging of the planetary nebula NGC 6720 (the Ring Nebula) is presented. We map emission-line fluxes of the lines (N II) lambda-lambda(5755, 6583), (S II) lambda-lambda(6717, 6731), (O I) lambda(6300), (O III) lambda(5007), He II lambda(4686), H-alpha, and H-Beta using the Ohio State Imaging Fabry-Perot Spectrograph. From these fluxes we derive maps of the (N II) electron temperature, (S II) electron density, Balmer decrement, and ionization diagnostics across the nebula. A sharp drop in ionization is seen along the entire outer edge of the nebula and the ionization edge is resolved and clumpy. We show that the (O I)-bright filaments are not substantially denser or cooler than the gas in which they are embedded. The (S II) density map shows two strong, clumpy density enhancements on the minor axis of the nebula, inside the outer edge. These density enhancements motivate our model of an oval-shaped toroid for the nebula. Publication: The Astronomical Journal Pub Date: November 1994 DOI: 10.1086/117199 Bibcode: 1994AJ....108.1860L Keywords: Balmer Series; Electron Energy; Electron Flux Density; Emission Spectra; H Alpha Line; H Beta Line; Ionization; Planetary Nebulae; Stellar Spectra; Stellar Spectrophotometry; Visible Spectrum; Astronomical Maps; Astronomical Photography; Calibrating; Data Reduction; Fabry-Perot Spectrometers; Imaging Spectrometers; Photometers; Spectrographs; Astronomy; PLANETARY NEBULAE: INDIVIDUAL: NGC 6720 full text sources ADS | data products SIMBAD (2)