Orion Bar
E460827
Orion Bar is a bright, elongated photodissociation region at the edge of the Orion Nebula, where intense ultraviolet radiation from young massive stars shapes and illuminates dense molecular gas and dust.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Orion Bar canonical | 2 |
How this entity was disambiguated
This entity first appeared as the object of triple T4617573 — 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: Orion Bar Context triple: [Orion Molecular Cloud Complex, contains, Orion Bar]
-
A.
Barnard 33
Barnard 33, commonly known as the Horsehead Nebula, is a small dark nebula in the constellation Orion whose distinctive horse-head shape is silhouetted against the bright emission nebula IC 434.
-
B.
Barnard's Loop
Barnard's Loop is a large, faint emission nebula forming a sweeping arc across the constellation Orion, believed to be the remnant of ancient supernova activity.
-
C.
30 Doradus
30 Doradus, also known as the Tarantula Nebula, is a vast and intensely active star-forming region and emission nebula in the Large Magellanic Cloud.
-
D.
Carina Nebula
The Carina Nebula is a vast, active star-forming region in the Milky Way known for its towering gas and dust pillars and dramatic young stellar clusters.
-
E.
Merope Nebula
The Merope Nebula is a bright reflection nebula in the Pleiades star cluster, illuminated by and surrounding the hot blue star Merope in the constellation Taurus.
- 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: Orion Bar Target entity description: Orion Bar is a bright, elongated photodissociation region at the edge of the Orion Nebula, where intense ultraviolet radiation from young massive stars shapes and illuminates dense molecular gas and dust.
-
A.
Barnard 33
Barnard 33, commonly known as the Horsehead Nebula, is a small dark nebula in the constellation Orion whose distinctive horse-head shape is silhouetted against the bright emission nebula IC 434.
-
B.
Barnard's Loop
Barnard's Loop is a large, faint emission nebula forming a sweeping arc across the constellation Orion, believed to be the remnant of ancient supernova activity.
-
C.
30 Doradus
30 Doradus, also known as the Tarantula Nebula, is a vast and intensely active star-forming region and emission nebula in the Large Magellanic Cloud.
-
D.
Carina Nebula
The Carina Nebula is a vast, active star-forming region in the Milky Way known for its towering gas and dust pillars and dramatic young stellar clusters.
-
E.
Merope Nebula
The Merope Nebula is a bright reflection nebula in the Pleiades star cluster, illuminated by and surrounding the hot blue star Merope in the constellation Taurus.
- F. None of above. chosen
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
astrophysical structure
ⓘ
photodissociation region ⓘ |
| astronomicalRegionType |
bright rim
ⓘ
ionization front ⓘ photon-dominated region ⓘ |
| contains |
atomic gas
ⓘ
dense molecular gas ⓘ interstellar dust ⓘ ionized gas ⓘ |
| distanceFromEarth |
approximately 1350 light-years
ⓘ
approximately 414 parsecs ⓘ |
| hasDensityGradient | true ⓘ |
| hasNearbyExcitingStars | Theta1 Orionis C ⓘ |
| hasPhysicalProcess |
heating by photoelectric effect on dust grains
ⓘ
molecular hydrogen excitation ⓘ photodissociation of molecules ⓘ photoevaporation flows ⓘ photoionization ⓘ polycyclic aromatic hydrocarbon emission ⓘ |
| hasSharpTransitionBetween | ionized gas and molecular gas ⓘ |
| hasStrongEmissionFrom |
carbon monoxide
ⓘ
fine-structure lines of ionized atoms ⓘ ionized carbon ⓘ molecular hydrogen ⓘ polycyclic aromatic hydrocarbons ⓘ |
| hasTemperatureGradient | true ⓘ |
| illuminatedBy | ultraviolet radiation ⓘ |
| isBright | true ⓘ |
| isEdgeOn | true ⓘ |
| isElongated | true ⓘ |
| isShapedBy | Theta1 Orionis C ⓘ |
| isTargetOf |
ALMA observations
ⓘ
Herschel Space Observatory observations ⓘ Hubble Space Telescope observations ⓘ Spitzer Space Telescope observations ⓘ |
| isUsedAs |
benchmark for interstellar chemistry models
ⓘ
benchmark for photon-dominated region models ⓘ template photodissociation region ⓘ |
| locatedIn |
Orion Molecular Cloud Complex
ⓘ
Orion Nebula ⓘ |
| locatedInConstellation | Orion ⓘ |
| observedIn |
infrared wavelengths
ⓘ
optical wavelengths ⓘ radio wavelengths ⓘ submillimeter wavelengths ⓘ ultraviolet wavelengths ⓘ |
| shapedBy | ultraviolet radiation ⓘ |
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: Orion Bar Description of subject: Orion Bar is a bright, elongated photodissociation region at the edge of the Orion Nebula, where intense ultraviolet radiation from young massive stars shapes and illuminates dense molecular gas and dust.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.