The inner abundance gradient of M33 using bright planetary nebulae

G. Stasinska¹, J. Vilchez, E. Perez, R. Gonzalez-Delgado, R. Corradi, A. Mampaso, L. Magrini

¹LUTH, Observatoire de Meudon, Meudon, France

The oxygen abundance in bright planetary nebulae is believed to be a good tracer of the oxygen abundance in a galaxy at the time when star formation has stopped. It can be used as a substitute to the oxygen abundance derived from HII regions, which is likely strongly biased at high metallicities. We report on an ongoing project aimed at deriving the inner abundance gradient in the spiral galaxy M33 using planetary nebulae instead of HII regions.