<P> 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 . </P>
<P> 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 . </P>
what makes cepheid variable stars useful in determining star distances
what makes cepheid variable stars useful in determining star distances
A strong direct relationship between a Cepheid variable 's luminosity and pulsation period
A strong direct relationship between a Cepheid variable 's luminosity and pulsation period