Classical Cepheid variable

Classical Cepheid variables are a type of pulsating star characterized by periodic changes in brightness due to expansion and contraction of their outer layers. They are typically supergiant stars that belong to the spectral types F or G, and they have well-defined periods of variability that range from a few days to several weeks. The key features of Classical Cepheids include: 1. **Pulsation**: These stars undergo regular pulsations, caused by changes in temperature and pressure in their outer layers.