Title: Morphology of the bipolar planetary nebula NGC 2346 from emission line profile studies
Abstract:High resolution observations of Hα 6563 Å, [O III] 5007 Å and [N II] 6583 Å emission lines in the bipolar planetary nebula NGC 2346 are presented. Expansion velocities (Vexp) of 8±1 km s−1 in the [O I...High resolution observations of Hα 6563 Å, [O III] 5007 Å and [N II] 6583 Å emission lines in the bipolar planetary nebula NGC 2346 are presented. Expansion velocities (Vexp) of 8±1 km s−1 in the [O III] line and 11±1 km s−1 in the [N II] line are observed in the central region. An expansion velocity of 7.5±1.0km s−1 in the [O III] line is observed in a position 10 arcsec away from the centre, in the NE lobe of the nebula. From the widths of the Hα and [N II] lines, an ion temperature of T = 10 650±2950 K and a turbulent velocity VT=16±2 km s−1 are derived. Using the detailed radial velocity mapping done by Walsh, a morphological model for the nebula is presented. We suggest that the observed relative intensities of the approaching and receding components of emission lines in this nebula may very well be interpreted as due to the particular line-of-sight geometry in which the nebula is oriented.Read More