Author: iamdefinitory

ERUPTIVE VARIABLES: Stars that experience irregular changes in brightness, including Cepheid variables, though they vary in different ways.

PULSATION MECHANISM: The process in which Cepheid variables expand and contract, driven by the balance between radiation pressure and gravity.

POPULATION II CEPHEIDS: Older, metal-poor Cepheid variables found in globular clusters or the galactic halo.

POPULATION I CEPHEIDS: Cepheid variables that are metal-rich, typically found in the disk of a galaxy.

BRIGHTNESS AND PERIODICITY: The intrinsic brightness of a Cepheid variable is directly related to its pulsation period, allowing astronomers to determine its distance.

DISTANCE LADDER: A series of methods used to measure astronomical distances, with Cepheid variables serving as one of the key methods for measuring distances to galaxies.

TYPE II CEPHEID: A type of Cepheid variable that is older and less massive than classical Cepheids, typically found in globular clusters.

CLASSICAL CEPHEID: Cepheid variables that are young, massive stars, used to measure distances within our galaxy and to nearby galaxies.

INSTABILITY STRIP: The region of the Hertzsprung-Russell diagram where Cepheid variables and other pulsating stars are located.

STANDARD CANDLE: An astronomical object whose luminosity is known, allowing it to be used to determine distances in space.