The Structure of NGC 6720: The Ring Nebula in Lyra

P.D. Atherton, T.R. Hicks, N.K. Reay, S.P. Worswick, W. Hayden Smith
1978 Symposium - International astronomical union  
New observations have been made of the [OIII] 5007Å ine profile from the central and outer regions of 6720 in order to study in detail the radial velocity structure of the nebula. This data was obtained using a Fabry-Perot Interferometer working at a resolution of 67,000. The line profile is clearly s p l i t in the centre indicating the presence of a gaseous envelope surrounding, and in radial expansion from, the central star at avelocity of 25 ±5 km/sec. Irregularities in the emission intensities indicate local patchiness in this shell.
doi:10.1017/s0074180900143177 fatcat:p52jy4ysc5hcbmhexvthysrvsy