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.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Leavitt law canonical | 1 |
| Leavitt’s law | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T6146138 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Leavitt law Context triple: [Henrietta Swan Leavitt, knownFor, Leavitt law]
-
A.
Aitken’s Law
Aitken’s Law is a phonological rule in Scots and Scottish English that governs when vowels are pronounced long or short depending on their phonetic and morphological environment.
-
B.
Kluge's law
Kluge's law is a proposed sound law in Proto-Germanic historical linguistics that explains the development of certain geminate consonants from earlier consonant clusters.
-
C.
Lusser's law
Lusser's law is a reliability engineering principle that states the overall reliability of a system is the product of the reliabilities of its individual components, highlighting how system reliability decreases as more components are added in series.
-
D.
Osthoff's law
Osthoff's law is a sound change in Indo-European linguistics describing the shortening of long vowels before resonant consonants followed by another consonant.
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E.
Szemerényi's law
Szemerényi's law is a sound law in Proto-Indo-European linguistics that explains the loss of certain final consonants with compensatory lengthening of the preceding vowel.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Leavitt law Target entity description: 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.
-
A.
Aitken’s Law
Aitken’s Law is a phonological rule in Scots and Scottish English that governs when vowels are pronounced long or short depending on their phonetic and morphological environment.
-
B.
Kluge's law
Kluge's law is a proposed sound law in Proto-Germanic historical linguistics that explains the development of certain geminate consonants from earlier consonant clusters.
-
C.
Lusser's law
Lusser's law is a reliability engineering principle that states the overall reliability of a system is the product of the reliabilities of its individual components, highlighting how system reliability decreases as more components are added in series.
-
D.
Osthoff's law
Osthoff's law is a sound change in Indo-European linguistics describing the shortening of long vowels before resonant consonants followed by another consonant.
-
E.
Szemerényi's law
Szemerényi's law is a sound law in Proto-Indo-European linguistics that explains the loss of certain final consonants with compensatory lengthening of the preceding vowel.
- F. None of above. chosen
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 ⓘ
linked to:
Cepheid variables
|
| 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
ⓘ
linked to:
Physical Cosmology
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 ⓘ |
| 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 ⓘ |
| isPartOf | cosmic distance ladder ⓘ |
| mathematicallyExpressedAs | linear relation between absolute magnitude and logarithm of period ⓘ |
| namedAfter | Henrietta Swan Leavitt ⓘ |
| playsRoleIn |
determination of the Hubble constant
ⓘ
testing cosmological models ⓘ |
| relatedTo |
Hubble–Lemaître law
ⓘ
linked to:
Lemaître–Hubble law
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 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Leavitt law Description of subject: 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.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.
1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud
→
citedAs
→
Leavitt’s law
ⓘ
linked to: Leavitt law