Discovering the Secrets of the Universe's Oldest Stars

The study provides the first framework for understanding extremely metal-poor (XMP) OB stars, key to exploring the early Universe. Using theoretical models, it calibrates stellar properties like temperature and ionizing photon flux, revealing XMP stars are hotter, more compact, and emit more ionizing radiation than their metal-rich counterparts. These findings aid in studying star formation and reionization in distant galaxies.