# distance modulus

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## distance modulus

(**moj**-ŭ-lŭs) The difference between the apparent magnitude,

*m*, and the absolute magnitude,

*M*, of a star and therefore a measure of distance (see magnitude):

*m*–

*M*= 5 log(

*d*/10) = 5 log

*d*– 5

where *d * is the distance in parsecs. Distance modulus is used to determine the distances of stars and stellar clusters. It is corrected for interstellar extinction by an additional term (see magnitude).

## Distance Modulus

in astronomy, the difference between the apparent (*m*) and absolute (*M*) magnitudes of a celestial body. This quantity is used to describe distances to stars and stellar systems. Whereas *M* depends only on the intrinsic luminosity of a star, *m* depends also on the distance *r* (in parsecs) to the star, that is, *m – M = 5* log *r —* 5.

## distance modulus

[′dis·təns ‚mäj·ə·ləs] (astronomy)