Abundances of Disk Planetary Nebulae in M31 and the Radial Oxygen Gradient

TL;DR

This study measures elemental abundances in 16 planetary nebulae in M31's disk, compares them with previous data and Milky Way PNe, and finds a shallower radial oxygen gradient in M31.

Contribution

It provides new spectroscopic data for M31 PNe and characterizes its radial oxygen gradient, enhancing understanding of galactic chemical evolution.

Findings

Median elemental abundances determined for 16 PNe.

Radial oxygen gradient in M31 is shallower than in the Milky Way.

Comparison shows differences in chemical enrichment between M31 and the Milky Way.

Abstract

We have obtained spectra of 16 planetary nebulae in the disk of M31 and determined the abundances of He, N, O, Ne, S and Ar. Here we present the median abundances and compare them with previous M31 PN disk measurements and with PNe in the Milky Way. We also derive the radial oxygen gradient in M31, which is shallower than that in the Milky Way, even accounting for M31's larger disk scale length.