IGNOU PHE 15 2018 - Explain how Cepheid variables can be used to measure astronomical dist

Question

Explain how Cepheid variables can be used to measure astronomical distances.

01 Feb 2018

Answer :

Word Count : 362

Cepheid variable stars are intrinsic variables which pulsate in a predicatable way. In addition, a Cepheid star's period (how often it pulsates) is directly related to its luminosity or brightness.

Image ignouacademy-com--p-cepheid-15170

Cepheid variables are extremely luminous and very distant ones can be observed and measured. Once the period of a distant Cepheid has been measured, its luminosity can be determined from the known behavior of Cepheid variables. Then its absolute magnitude and apparent magnitude can be related by

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