A variable star having a regular cycle of brightness with a frequency related to its luminosity, so allowing estimation of its distance from the earth.‘Shapley also pointed out in that paper that the noted increase in the distance of the clouds explains the ‘failure of the persistent Harvard searches for cluster-type cepheids in the Magellanic Clouds and their globular clusters.’’
- ‘The size and age of the expanding Universe is calculated by astronomers on the basis of winking stars called cepheids, the nearest of which is 1000-2000 light years away.’
- ‘Several hundred cepheid variables are known in our Galaxy.’
- ‘Using this, astronomers only needed to know the period of a cepheid variable to figure out how bright, and therefore how far away it was.’
- ‘Type I cepheids are most closely associated with the thin disc and the spiral arm components of the Galaxy.’
Early 20th century from the name of the variable star Delta Cephei, which typifies this class of stars.