Cepheid

Part of speech: noun

Definitions

1. An astronomical phenomenon that shows consistent changes in brightness over a defined period and serves as a reliable tool for measuring cosmic distances
2. A stellar entity that undergoes regular pulsations in luminosity, which astronomers utilize to gauge distances across the universe
3. A type of variable star that exhibits periodic variations in brightness, allowing astronomers to use these fluctuations as a method for determining distances in space

Etymology: The name of this class of star reaches back to Cepheus, a king of Greek myth. In the Greek legend, Cepheus was the father of Andromeda, and he was honoured by being placed among the stars as a constellation in the northern sky. The Latin form "Cepheus" gave astronomers the adjective "Cephei," meaning "of Cepheus," which was used to name stars in that constellation. The star type takes its name from Delta Cephei, the fourth-brightest star in that constellation, whose regular brightening and dimming was studied closely. The ending "-id" was attached to the Latin genitive "Cephei" to form a noun for stars of this kind, following the pattern of naming a class after a prominent example.