The first 8-13 μm spectra of globular cluster red giants:: circumstellar silicate dust grains in 47 Tucanae (NGC 104)

We present 8-13 mu m spectra of eight red giants in the globular cluster 47 Tucanae (NGC104), obtained at the European Southern Observatory 3.6 m telescope. These are the first mid-infrared spectra of metal-poor, low-mass stars. The spectrum of at least one of these, namely the extremely red, large-amplitude variable V1, shows direct evidence of circumstellar grains made of amorphous silicate.