Grus I

Grus I is an ultra-faint satellite galaxy located at 120 kiloparsecs from Earth, possessing a luminosity of -3.4 and a size of 60 parsecs. Based on its luminosity and size, this satellite might be appropriately categorized as a dwarf galaxy. This satellite galaxy exhibits a remarkably low average metallicity, determined through a combination of existing spectroscopic data and comprehensive IMACS spectroscopic follow-up studies on confirmed members. This revised spectroscopic metallicity is notably lower than previous estimations, suggesting Grus I is among the dwarf galaxies with the lowest metallicities. The velocity dispersion observed in this galaxy supports the classification of Grus I as an ultra-faint dwarf galaxy.