1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud
E571549
The 1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud is Henrietta Swan Leavitt’s landmark work that revealed the period–luminosity relationship of Cepheid variable stars, providing a crucial tool for measuring cosmic distances.
All labels observed (1)
| Label | Occurrences |
|---|---|
| 1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T6146146 — 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: 1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud Context triple: [Henrietta Swan Leavitt, notableWork, 1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud]
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A.
On the Relations between the Spectra and Other Characteristics of the Stars
"On the Relations between the Spectra and Other Characteristics of the Stars" is a landmark 1914 paper by Henry Norris Russell that helped establish the relationship between stellar spectral type, luminosity, and other properties, laying groundwork for the Hertzsprung–Russell diagram and modern stellar astrophysics.
-
B.
On the Sizes and Distances of the Sun and Moon
On the Sizes and Distances of the Sun and Moon is an ancient Greek astronomical treatise that presents one of the earliest known geometric attempts to quantify the relative sizes and distances of the Sun and Moon from Earth.
-
C.
Eddington standard model of stars
The Eddington standard model of stars is a theoretical framework in stellar astrophysics that describes the internal structure and energy transport of stars under simplifying assumptions of radiative equilibrium and constant opacity.
-
D.
A Relation between Distance and Radial Velocity among Extra-Galactic Nebulae
"A Relation between Distance and Radial Velocity among Extra-Galactic Nebulae" is Edwin Hubble’s landmark 1929 paper that established the linear relationship between galaxies’ distances and their recessional velocities, providing the first strong evidence for the expanding universe.
-
E.
Hubble–Humason galaxy redshift measurements
The Hubble–Humason galaxy redshift measurements are a landmark set of observations that extended and refined Edwin Hubble’s work on the expanding universe by systematically measuring the redshifts of distant galaxies.
- 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: 1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud Target entity description: The 1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud is Henrietta Swan Leavitt’s landmark work that revealed the period–luminosity relationship of Cepheid variable stars, providing a crucial tool for measuring cosmic distances.
-
A.
On the Relations between the Spectra and Other Characteristics of the Stars
"On the Relations between the Spectra and Other Characteristics of the Stars" is a landmark 1914 paper by Henry Norris Russell that helped establish the relationship between stellar spectral type, luminosity, and other properties, laying groundwork for the Hertzsprung–Russell diagram and modern stellar astrophysics.
-
B.
On the Sizes and Distances of the Sun and Moon
On the Sizes and Distances of the Sun and Moon is an ancient Greek astronomical treatise that presents one of the earliest known geometric attempts to quantify the relative sizes and distances of the Sun and Moon from Earth.
-
C.
Eddington standard model of stars
The Eddington standard model of stars is a theoretical framework in stellar astrophysics that describes the internal structure and energy transport of stars under simplifying assumptions of radiative equilibrium and constant opacity.
-
D.
A Relation between Distance and Radial Velocity among Extra-Galactic Nebulae
"A Relation between Distance and Radial Velocity among Extra-Galactic Nebulae" is Edwin Hubble’s landmark 1929 paper that established the linear relationship between galaxies’ distances and their recessional velocities, providing the first strong evidence for the expanding universe.
-
E.
Hubble–Humason galaxy redshift measurements
The Hubble–Humason galaxy redshift measurements are a landmark set of observations that extended and refined Edwin Hubble’s work on the expanding universe by systematically measuring the redshifts of distant galaxies.
- F. None of above. chosen
Statements (45)
| Predicate | Object |
|---|---|
| instanceOf |
astronomy paper
ⓘ
scientific paper ⓘ |
| alsoKnownAs | Leavitt’s period–luminosity paper NERFINISHED ⓘ |
| associatedPerson | Edward Charles Pickering NERFINISHED ⓘ |
| author | Henrietta Swan Leavitt NERFINISHED ⓘ |
| basedOn | photographic plate observations from the Harvard College Observatory ⓘ |
| chronology | follows earlier Harvard College Observatory work on variable stars in the Magellanic Clouds ⓘ |
| citedAs | Leavitt’s law NERFINISHED ⓘ |
| citedBy | Edwin Hubble’s work on extragalactic distances ⓘ |
| countryOfPublication |
United States of America
ⓘ
surface form:
United States
|
| dataSource | Harvard College Observatory photographic plate archive NERFINISHED ⓘ |
| era | early 20th century astronomy ⓘ |
| field |
astronomy
ⓘ
astrophysics ⓘ |
| historicalContext | produced during the era of the Harvard Computers ⓘ |
| impact |
contributed to the establishment of the cosmic distance ladder
ⓘ
enabled later determination of the size of the Milky Way and nearby galaxies ⓘ laid the foundation for Edwin Hubble’s measurement of the distance to the Andromeda Galaxy ⓘ provided a distance scale tool for measuring extragalactic distances ⓘ |
| influenced |
calibration of the Hubble constant
ⓘ
development of modern cosmology ⓘ |
| institution | Harvard College Observatory NERFINISHED ⓘ |
| language | English ⓘ |
| mainContribution |
discovery of a tight correlation between the periods and apparent magnitudes of Cepheid variables in the Small Magellanic Cloud
ⓘ
establishment of Cepheid variables as standard candles for distance measurement ⓘ formulation of the period–luminosity relationship for Cepheid variables ⓘ |
| objectOfStudy |
25 Cepheid variable stars
ⓘ
variable stars in the Small Magellanic Cloud ⓘ |
| observationalSite | Harvard College Observatory NERFINISHED ⓘ |
| observationalTechnique | repeated photographic imaging of the Small Magellanic Cloud ⓘ |
| publicationYear | 1912 ⓘ |
| publishedIn | Harvard College Observatory Circular NERFINISHED ⓘ |
| relatedConcept |
distance modulus
ⓘ
extragalactic distance scale ⓘ standard candle ⓘ |
| relatedWork | Henrietta Swan Leavitt’s earlier catalogs of variable stars in the Magellanic Clouds NERFINISHED ⓘ |
| result |
demonstration that longer-period Cepheids are intrinsically brighter than shorter-period ones
ⓘ
empirical calibration of a relation between period and apparent magnitude for SMC Cepheids ⓘ |
| scientificSignificance |
cornerstone of observational cosmology
ⓘ
key step in establishing that the universe extends beyond the Milky Way ⓘ |
| topic |
Cepheid variable stars
ⓘ
Small Magellanic Cloud NERFINISHED ⓘ period–luminosity relation ⓘ |
| usesMethod |
period determination from light curves
ⓘ
photographic photometry ⓘ |
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: 1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud Description of subject: The 1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud is Henrietta Swan Leavitt’s landmark work that revealed the period–luminosity relationship of Cepheid variable stars, providing a crucial tool for measuring cosmic distances.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.
Henrietta Swan Leavitt
→
notableWork
→
1912 paper on periods of 25 Cepheid variables in the Small Magellanic Cloud
ⓘ