what is the first variation?
A type of star that pulsates radially, varying in both diameter and temperature
Cepheid variable
A Cepheid variable () is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude.
do all stars spend the same amount of time on the main sequence The total life span can be estimated, to first approximation, as the total energy produced divided by the star's luminosity. what is main sequence? Continuous and distinctive band of stars that appears on plots of stellar color versus brightness. describe a few of its properties? Majority of stars on a typical HR diagram lie along the main-sequence curve and temperature of a star determines its spectral type mention a few variations in luminosity color? Cepheid variables, Delta Scuti variables, and Beta Cephei variables
wiki:5279429
Cepheid variable [SEP] Introduction
A Cepheid variable () is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude. A strong direct relationship between a Cepheid variable's luminosity and pulsation period established Cepheids as important indicators of cosmic benchmarks for scaling galactic and extragalactic distances. This robust characteristic of classical Cepheids was discovered in 1908 by Henrietta Swan Leavitt after studying thousands of variable stars in the Magellanic Clouds. This discovery allows one to know the true luminosity of a Cepheid by simply observing its pulsation period. This in turn allows one to determine the distance to the star, by comparing its known luminosity to its observed brightness.