Echelle spectroscopy of the nuclei of the highly collimated bipolar planetary nebulae M 2-9 and M 1-91

Abstract

We present echelle spectroscopy of the unresolved nuclei of the bipolar planetary nebulae M 2-9 and M 1-91. The spectrum is dominated by emission lines emitted under a wide range of physical conditions. From the observations we identify the emission lines, derive physical conditions and relative motions of the different ionized species in the circumstellar region of both objects. We propose that the observed forbidden lines arise in the inner part of the extended torus that surrounds each object.