EXTREME NITROGEN ENRICHMENT IN THE ASYMMETRICAL PLANETARY-NEBULA M1-75

In the framework of the morphological survey of northern sky planetary nebulae, in progress at the IAC, we investigate in detail those nebulae that show peculiarities or that have not been studied before. By means of narrowband imaging and accurate two-dimensional spectroscopy we analyzed the peculiar nebula M1-75. Its morphology is very complex, consisting of two contiguous shells, surrounded by two previously undetected fainter lobes. Detailed plasma analysis showed an extreme nitrogen enrichment in the outermost shell (N/O = 2.85), as well as a high helium abundance (He/H = 0.18), making this object a good candidate for peculiar stellar evolutionary paths. The detected abundances of heavy elements are among the highest ever detected in a galactic planetary nebula.