She noticed that a type of star known as a Cepheid variable (after the constellation Cepheus, where it first was identified) pulsated with a regular rhythm-a kind of stellar heartbeat.

她注意到，有一种名叫造父变星（以仙王星座命名，第一颗造父变星就是在那里发现的）的恒星在有节奏地搏动——一种星体的“心跳”。