We present Spitzer Space Telescope IRAC and MIPS observations of the Galactic globular cluster M15 (NGC 7078), one of the most metal-poor clusters, with a [Fe/H] = -2.4. Our Spitzer images reveal a population of dusty red giants near the cluster center, a previously detected planetary nebula designated K648, and a possible detection of the intracluster medium arising from mass-loss episodes from the evolved stellar population. Our analysis suggests that (9 ± 2) × 10 -4 M ⊖ of dust is present in the core of M15, and that this material has accumulated over a period of ≈ 10 6 yr, a timescale 10 times shorter than the last Galactic plane crossing event. We also present Spitzer 1RS follow-up observations of K648, including the detection of the [Ne II] 12.81 μm line, and discuss abundances derived from infrared fine-structure lines.
- Globular clusters: individual (M15)
- ISM: evolution
- Planetary nebulae: individual (K648)
- Stars: AGB and post-AGB
- Stars: mass loss