Overview

• A Nature Astronomy paper introduces a model linking the 21 cm hydrogen signal to the masses of the first stars by consistently incorporating ultraviolet and X-ray emissions from early X-ray binaries.
• Researchers found X-ray binaries in Population III star systems are both brighter and more numerous than previously estimated, intensifying their impact on the 21 cm signal.
• The 21 cm wavelength emission, arising from a hydrogen spin-flip transition roughly 100 million years after the Big Bang, serves as a key marker of cosmic dawn.
• The REACH telescope is undergoing calibration in South Africa’s Karoo region while the SKA array advances construction in Australia and South Africa, with operations expected to begin in 2027.
• Study co-authors Anastasia Fialkov and Eloy de Lera Acedo say the upcoming data could illuminate how early stellar masses and compositions differ from those of modern stars.