The Ultraviolet Mystery Inside Newborn Stars

Young stars buried deep in molecular clouds are bathed in ultraviolet radiation, but they shouldn’t be. Protostars are too cold and dim to produce UV light themselves, yet James Webb Space Telescope observations of five stellar nurseries in Ophiuchus reveal its unmistakable signature affecting the surrounding gas. Astronomers tested the obvious explanation that nearby massive stars illuminate these birthplaces but subsequently ruled it out. The UV radiation must be coming from inside the star forming regions themselves, forcing a fundamental rethink of how stars are born.