Lines in the Planetary Nebula NGC 7009: Implications for Dual-Abundance Models APPROVED BY SUPERVISING COMMITTEE:

I would like to express my deepest gratitude to my adviser, Dr. Harriet L. Dinerstein, for her continuous support and guidance throughout the completion of this study. Were it not for her valuable teaching both in academics and in everyday life, the completion of this thesis would not have been possible. I am also highly grateful for the help of the other members of my committee