Program: GS-2020B-Q-228

At present there are just 30+6 withe dwarfs (WDs) known to be the nuclei of planetary nebulae (PNe). This six object were classified recently in the first stage of this project. By means of GMOS medium resolution spectroscopy, we want to identify the ionizing stars of faint and evolved PNe. We propose to use GMOS in the long-slit configuration to study faur PN-WDs candidates. These stars were selected from the color-color diagrams built with previous, poor-weather, Gemini data. With this strategy we hope to increase the number of known ionizing, central stars of old PN and, by characterizing them, to contribute to our understanding of the final stages of the stellar evolution.