Poster abstract details

We report on 16 planetary nebulae (PNe) in the disk of M31, observed spectroscopically at APO and Gemini-N. These PNe, taken from Merrett et al. (2006) are located between 15 and 50 arcminutes from the major axis, and are not associated with any known satellites or star streams. We detected [O III] $\lambda$4363 in all of the objects, allowing for direct temperature determination. We find O/H ranging from half to slightly above solar, comparable to Milky Way disk PNe (Henry et al. 2010). We also find N/O from solar to several times solar. Finally, we use the oxygen abundances to derive a radial gradient, which we find to be shallower than the one in the Milky Way, even after accounting for M31’s larger disk scale length.