Davide Massari

In the crowded center of the Milky Way, individual stars are hard to pick out, but that's exactly where Patchick 126 hides — a faint cluster that has long resisted confident classification. Astronomers pointed the infrared spectrograph IGRINS and the Hubble Space Telescope at it to study its chemistry and age in detail for the first time.

The oven that once baked the first stars has long gone cold, but crumbs from that bread remain. These crumbs are carbon atoms scattered on the surfaces of old stars in tiny satellite galaxies of the Milky Way. Such galaxies are called ultra-faint dwarfs: each contains only a few thousand stars and shines barely perceptibly.