The stars are known as Cepheid variables.

这些恒星就是我们熟知的造父变星。

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”。

These are called Cepheid variables, and they were critically important, because it was known that the time it took them to pulse was directly related to their luminosity, how much energy they emitted.

这些被称为造父变星，它们非常重要，因为我们知道它们产生脉冲的时间与它们的光度直接相关，也就是它们释放的能量。