IAU 1991 Resolution A4
E497210
IAU 1991 Resolution A4 is an International Astronomical Union standard that formalized modern relativistic time scales and reference systems used in astronomy and geodesy.
All labels observed (2)
| Label | Occurrences |
|---|---|
| IAU 1991 Resolution A4 canonical | 1 |
| IAU 1991 resolutions | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T5150742 — 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: IAU 1991 Resolution A4 Context triple: [Terrestrial Time, definedIn, IAU 1991 Resolution A4]
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A.
General Assembly of the IAU
The General Assembly of the IAU is the International Astronomical Union’s principal global meeting, where astronomers convene to discuss scientific results, set standards, and make key organizational and nomenclature decisions.
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B.
International Celestial Reference System
The International Celestial Reference System is the standard, high-precision coordinate framework used in astronomy and geodesy to define positions of celestial objects relative to distant quasars.
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C.
IAU Working Groups
IAU Working Groups are specialized expert committees within the International Astronomical Union that focus on specific scientific, technical, or organizational topics in astronomy and astrophysics.
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D.
International Astronomical Union
The International Astronomical Union is the global organization of professional astronomers responsible for standardizing astronomical nomenclature and definitions, including constellations and celestial bodies.
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E.
IAU Divisions
IAU Divisions are the major scientific branches within the International Astronomical Union that organize and coordinate research and activities across different subfields of astronomy.
- 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: IAU 1991 Resolution A4 Target entity description: IAU 1991 Resolution A4 is an International Astronomical Union standard that formalized modern relativistic time scales and reference systems used in astronomy and geodesy.
-
A.
General Assembly of the IAU
The General Assembly of the IAU is the International Astronomical Union’s principal global meeting, where astronomers convene to discuss scientific results, set standards, and make key organizational and nomenclature decisions.
-
B.
International Celestial Reference System
The International Celestial Reference System is the standard, high-precision coordinate framework used in astronomy and geodesy to define positions of celestial objects relative to distant quasars.
-
C.
IAU Working Groups
IAU Working Groups are specialized expert committees within the International Astronomical Union that focus on specific scientific, technical, or organizational topics in astronomy and astrophysics.
-
D.
International Astronomical Union
The International Astronomical Union is the global organization of professional astronomers responsible for standardizing astronomical nomenclature and definitions, including constellations and celestial bodies.
-
E.
IAU Divisions
IAU Divisions are the major scientific branches within the International Astronomical Union that organize and coordinate research and activities across different subfields of astronomy.
- F. None of above. chosen
Statements (51)
| Predicate | Object |
|---|---|
| instanceOf |
IAU resolution
ⓘ
astronomical standard ⓘ time scale standard ⓘ |
| adoptedAt | 21st General Assembly of the IAU NERFINISHED ⓘ |
| adoptedBy | International Astronomical Union NERFINISHED ⓘ |
| adoptedInCity | Buenos Aires NERFINISHED ⓘ |
| adoptedInYear | 1991 ⓘ |
| appliesTo |
VLBI observations
ⓘ
high-precision time and frequency transfer ⓘ satellite geodesy ⓘ solar system dynamics ⓘ spacecraft navigation ⓘ |
| basedOnTheory | general relativity ⓘ |
| defines |
Barycentric Celestial Reference System
NERFINISHED
ⓘ
Barycentric Coordinate Time NERFINISHED ⓘ Geocentric Celestial Reference System NERFINISHED ⓘ Geocentric Coordinate Time NERFINISHED ⓘ Terrestrial Time NERFINISHED ⓘ metric tensors for barycentric and geocentric reference systems ⓘ relationship between TCB and TCG ⓘ relationship between TCG and TT ⓘ relationship between coordinate times and proper time ⓘ relativistic equations of motion for artificial satellites ⓘ relativistic equations of motion for celestial bodies ⓘ relativistic framework for reference systems ⓘ relativistic scaling of mass parameters ⓘ relativistic scaling of space-time coordinates ⓘ relativistic scaling of spatial coordinates ⓘ relativistic scaling of time coordinates ⓘ relativistic treatment of Doppler effect ⓘ relativistic treatment of aberration ⓘ relativistic treatment of astrometric observables ⓘ relativistic treatment of frequency transfer ⓘ relativistic treatment of gravitational time delay ⓘ relativistic treatment of light propagation ⓘ relativistic treatment of parallax ⓘ relativistic treatment of time transfer ⓘ |
| field |
astrometry
ⓘ
astronomy ⓘ celestial mechanics ⓘ geodesy ⓘ relativistic reference systems ⓘ timekeeping in astronomy ⓘ |
| language | English ⓘ |
| purpose |
to formalize modern relativistic reference systems
ⓘ
to formalize modern relativistic time scales ⓘ to provide a consistent relativistic framework for celestial mechanics ⓘ to provide a consistent relativistic framework for geodesy ⓘ to provide a consistent relativistic framework for high-precision astrometry ⓘ |
| supersededInPartBy |
IAU 2000 resolutions on reference systems
NERFINISHED
ⓘ
IAU 2006 resolutions on time scales NERFINISHED ⓘ |
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: IAU 1991 Resolution A4 Description of subject: IAU 1991 Resolution A4 is an International Astronomical Union standard that formalized modern relativistic time scales and reference systems used in astronomy and geodesy.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
Terrestrial Time
this entity surface form:
IAU 1991 resolutions