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http://dx.doi.org/10.5467/JKESS.2007.28.7.847

Kinematics and Geometrical Structure of the Planetary Nebula NGC 6881  

Lee, Sang-Min (School of Science Education, Chungbuk National University)
Hyung, Siek (School of Science Education, Chungbuk National University)
Publication Information
Journal of the Korean earth science society / v.28, no.7, 2007 , pp. 847-856 More about this Journal
Abstract
The Planetary nebula NGC 6881 displays quadrupole morphology and it also has a jet feature in its image. We investigated the line profiles of the optical region spectral emission lines, using the Hamilton Echelle Spectrograph (HES) at the Lick observatory. The HES data obtained in this study was the radiation coming from the inner region within the diameter of 4 second of arc. Expansion velocity was obtained, based on the strong emission line profiles of e.g. H, Hel, Hell, [OIII], [NII], [ArIII], [SII], and [SIII}, using the IRAF and StarLink/Dipso reduction packages. The HI recombination lines showed one single peak profile, while the He and forbidden strong lines displayed double peaks. The results of this study show that the outflow velocity of gas increases radially outwards due to the central stellar radiation pressure. It was concluded that three central rings appeared in the HST image are the result of a combined structure of bipolar cones (seen in e.g. HI lines) and a ring (seen in He, [SIII] lines) in projection.
Keywords
ISM; planetary nebula; spectroscopic observation; NGC 6881;
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