Leavitt law

E571548

The Leavitt law is the period–luminosity relation for Cepheid variable stars that enables astronomers to measure cosmic distances and determine the scale of the universe.

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Statements (45)

Predicate Object
instanceOf astronomical relation
distance indicator
period–luminosity relation
accuracyImprovedBy corrections for reddening and extinction
observations in infrared bands
appliesTo Cepheid variable star
Classical Cepheid variable
Type I Cepheid NERFINISHED
assumes Cepheids in the same galaxy are at nearly the same distance
calibratedUsing Gaia mission parallaxes
Hubble Space Telescope observations
trigonometric parallax of nearby Cepheids
category Observational cosmology NERFINISHED
Stellar astronomy
describesRelationBetween intrinsic luminosity of Cepheid variables
pulsation period of Cepheid variables
enables calibration of the cosmic distance ladder
determination of extragalactic distances
measurement of cosmic distances
hasAlternativeName period–luminosity relation
hasDiscoverer Henrietta Swan Leavitt NERFINISHED
hasKeyParameter slope of the period–luminosity relation
zero point of the period–luminosity relation
hasLimitation metallicity dependence of the relation
scatter due to interstellar extinction
hasVariant infrared period–luminosity relation
period–luminosity–color relation
historicalSignificance provided first reliable method to measure distances to external galaxies
implies longer-period Cepheids are more luminous
influencedWorkOf Edwin Hubble NERFINISHED
isPartOf cosmic distance ladder NERFINISHED
mathematicallyExpressedAs linear relation between absolute magnitude and logarithm of period
namedAfter Henrietta Swan Leavitt NERFINISHED
playsRoleIn determination of the Hubble constant
testing cosmological models
relatedTo Hubble–Lemaître law NERFINISHED
standard candle concept
requiresCalibrationBy independent distance measurements
subjectOf cosmological distance scale studies
usedFor calibrating Type Ia supernova distances
determining the scale of the universe
measuring distances to nearby galaxies
measuring distances within the Milky Way
wasDiscoveredIn early 20th century
wasFirstFormulatedFromObservationsOf Cepheid variables in the Small Magellanic Cloud

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Henrietta Swan Leavitt knownFor Leavitt law