出典:Wikipedia
出典:『Wikipedia』 (2011/06/08 16:11 UTC 版)
A Cepheid (
/ˈsɛfiːɪd/ or /ˈsiːfiːɪd/) is a member of a class of very luminous variable stars. The strong direct relationship between a Cepheid variable's luminosity and pulsation period, secures for Cepheids their status as important standard candles for establishing the Galactic and extragalactic distance scales.