Alphecca

Its story

Alphecca, also called Gemma, is the jewel set into the Northern Crown, that small semicircular diadem painted into the northern sky by the Greeks and Romans. It shines with white A-type light, faintly variable because an unseen companion eclipses it briefly every seventeen days or so. At only 75 light-years away, its present glow set out around 1951, when the early jet age was just beginning to compress the world.