Cepheid stars pulsate in regular intervals typically in the range from 1 to 100 days. The stars themselves are yellowish giants or [[supergiant|supergiants]], five to twenty times more massive than and up to 30,000 times as luminous as the [[Sun]]. This intense brightness allows for Cepheids to be measured in other [[galaxy|galaxies]] for extra-galactic distances.<ref>http://www.daviddarling.info/encyclopedia/C/Cepheid_variable.html</ref> | Cepheid stars pulsate in regular intervals typically in the range from 1 to 100 days. The stars themselves are yellowish giants or [[supergiant|supergiants]], five to twenty times more massive than and up to 30,000 times as luminous as the [[Sun]]. This intense brightness allows for Cepheids to be measured in other [[galaxy|galaxies]] for extra-galactic distances.<ref>http://www.daviddarling.info/encyclopedia/C/Cepheid_variable.html</ref> |