The term cepheid originates from Delta Cephei in the constellation Cepheus , the first star of this type identified , by John Goodricke in 1784 .
Cepheid variables are divided into several subclasses which exhibit clearly different masses , ages , and evolutionary histories : The first cepheid known was Delta Cephei in the constellation Cepheus , found by John Goodricke in 1784 .