The kinematics of NGC 4361, a Population II planetary nebula with a bipolar outflow

High-resolution, spatially-resolved profiles of H alpha, He II lambda 6560 and [O III] lambda 5007 and deep narrow-band CCD images in the Hm and [O II I] lambda 5007 emission lines have been obtained of the planetary nebula (P N) NGC 4361. In addition, VLA-DnC lambda 3.6-cm continuum observations are presented, This material allows one to explore in unprecedented detail the morphology and kinematics of this PN, The morphology of this object is comp lex given the highly filamentary structure of the envelope, which is confir med to possess a low mass, The halo has a high expansion velocity that yiel ds incompatible kinematic and evolutionary ages, unless previous accelerati on of the nebular expansion is considered. However, the most remarkable res ult from the present observations is the detection of a bipolar outflow in NGC 4361, which is unexpected in a PN with a Population II low-mass-core pr ogenitor. It is shown that shocks resulting from the interaction of the bip olar outflow with the outer shell are able to provide an additional heating source in this nebula.