Polaris Aa size and scale context

Polaris Aa is the yellow supergiant at the heart of the North Star system and the nearest classical Cepheid to Earth. Because Cepheids act as standard candles for measuring cosmic distances, this pulsating star is far more than a navigation marker: it is one of astronomy’s key calibration beacons. Read its scale context, comparisons, and journey links on the canonical object page.