How did Hubble use cephaid variable stars to measure the distance of galaxies? I know they...

How did Hubble use cephaid variable stars to measure the distance of galaxies? I know they pulsate in a predictable way, how is this measured?

Expert Solution

cepheid are stars which brighten and dim periodically. This property allows them to be used as the comic yardstick to find the distance. They have a relationship between their luminosity and pulsation period.

in order to find the distance cepheid variables are used. cepheid variables are intrinsic variables which pulsate in a particular way their period is directly related to luminosity.

Its luminosity is measured by the behaviour of cepheid variables and is calculated by distance modulus equation

m - M = 5 log d - 5

where m = apparent magnitude of the object

M = absolute magnitude of the object

d = distance of the object in parsec.

genius_generous answered 2 years ago

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