Classical Cepheid and RR Lyrae variables are radially pulsating stars that trace young and old-age stellar populations, respectively. These classical pulsating stars are the most sensitive probes for the precision stellar astrophysics and the extragalactic distance measurements. Despite their extensive use as standard candles thanks to their well-defined Period–Luminosity relations, distance measurements based on these objects suffer from their absolute primary calibrations, metallicity effects, and other systematic uncertainties. Here, I present a review of classical Cepheid, RR Lyrae and type II Cepheid variables starting with a historical introduction and describing their basic evolutionary and pulsational properties. I will focus on recent theoretical and observational efforts to establish absolute scale for these standard candles at multiple wavelengths. The application of these classical pulsating stars to high-precision cosmic distance scale will be discussed along with observational systematics. I will summarize with an outlook for futher improvements in our understanding of these classical pulsators in the upcoming era of extremely large telescopes.

中文翻译：

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使用经典脉动星进行高精度距离测量

古典造父变星和天琴座RR变星是径向脉动的恒星，分别追踪年轻和年老的恒星群。这些经典的脉动星是精密恒星天体物理学和河外距离测量最灵敏的探测器。尽管由于它们明确定义的周期-光度关系，它们被广泛用作标准烛光，但基于这些物体的距离测量受到其绝对初级校准、金属丰度影响和其他系统不确定性的影响。在这里，我将回顾经典的造父变星、天琴座RR和II型造父变星，从历史介绍开始并描述它们的基本进化和脉动特性。我将专注于最近的理论和观察工作，以在多个波长下为这些标准烛光建立绝对比例。这些经典脉动星在高精度宇宙距离尺度上的应用将与观测系统学一起讨论。在即将到来的超大望远镜时代，我将总结我们对这些经典波轮的理解的进一步改进。