Much of the new dust in the interstellar medium is produced in the Asymptotic Giant Branch (AGB)
phase of evolution for low- to intermediate-mass stars. This dust is processed throughout the
remainder of stellar evolution, up to and including the planetary nebula phase. Studies of planetary
nebulae in irregular galaxies in the Local Group (mostly focused on the Magellanic Clouds) have
shown that low metallicity favours carbon-rich dust production. However, at ~1/3 and ~1/5 times
the solar metallicity respectively, they provide two snapshots of dust composition at low
metallicity, emphasising the need to investigate a region with a broader range of metallicity
values. With its abundance gradient up to Galactocentric distances of 10 kpc, our Galaxy is an ideal
laboratory for studying the dust composition at varying metallicity. I will discuss my work,
involving a spectroscopic analysis of a sample of planetary nebulae in the Galactic anti-center from
the Spitzer Space Telescope. In particular, the continuation of the abundance gradient has been
investigated in the outskirts of the Milky Way, as well as the dust composition in this presumably
metal-poor region. I will also briefly introduce some works in progress, one involving planetary
nebulae in the Galactic halo, and another investigating a few fullerene-containing planetary
nebulae.
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