Morpho-Kinematic Analysis of PNe with Intense [N II] and [S II] Emission Lines

Abstract

From the sample of 613 PNe used in the paper ‘Revised Diagnostic Diagrams for Planetary Nebulae’ (Riesgo & López, 2006) we have isolated a subsample of 51 PNe defined by log [H$\alpha$/[N II]]$<0$ and log [H$\alpha$/[S II]] $<0.4$. These objects have extremely intense [N II] and [S II] lines with respect to H$\alpha$ and are indicative of either very low excitation and/or high optical depth conditions, abundance effects in the case of N or cooling effects in shock excited regions, such as those expected in high velocity, collimated outflows. We have undertaken an imaging and detailed kinematic study of all the members of the subsample visible from the northern hemisphere. In this work we discuss the results and some correlations found between the anomalous line ratios in these objects and their morphological and kinematic characteristics.