Unraveling the Mystery of the Faintest Galaxies: A Deep Dive into Sagittarius II and Aquarius II

Astronomers used the Gemini/GHOST spectrograph to study Sagittarius II (Sgr2) and Aquarius II (Aqu2), two faint Milky Way satellites. Their analysis suggests Aqu2 is a dark matter-dominated ultra-faint dwarf galaxy, while Sgr2 remains ambiguous, possibly a star cluster. Chemical signatures and star movements were key to these classifications. The study highlights the difficulty in distinguishing faint galaxies from clusters and the need for further observations and simulations.