Delta Cephei: Astronomy’s Royal Gem Fit for a King

The variable star Delta Cephei lies in the constellation Cepheus and is a one of the most important and historical stars in astronomy. Delta Cep makes the basis for all Cepheids, which Henrietta Leavitt discoveed that their luminosities are directly related to their periods of pulsation. This led to our being able to measure greater distances starting when Edwin Hubble uncovered the distance to the Andromeda Galaxy after finding a Cepheid in the galaxy.