Unearthing Ancient Stars: The Hidden History of the Boötes I Dwarf Galaxy

Muratore et al. (2025) used Hubble and JWST data to study the ultra-faint dwarf galaxy Boötes I, revealing that about 85% of its stars have very low metallicities ([Fe/H] < −2). They found a total binary fraction of ~30%, similar to that in star clusters of comparable mass. These results show Boötes I is an ancient “fossil” galaxy, preserving stars from the Universe’s earliest generations.