Delta Cepheid

Delta Cephei (δ Cep, δ Cephei) is a quadruple star system located approximately 887 light-years away in the northern constellation of Cepheus, the King. At this distance, the visual magnitude of the star is diminished by 0.23 as a result of extinction caused by gas and dust along the line of sight. It is the prototype of the Cepheid variable stars that undergo periodic changes in luminosity.
Delta Cephei was discovered to... plus