Sharpless 45
E504051
Sharpless 45 is an emission nebula in the constellation Sagittarius, better known as the Omega Nebula, notable for its bright star-forming regions and distinctive swan-like shape.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Sharpless 45 canonical | 2 |
How this entity was disambiguated
This entity first appeared as the object of triple T5219554 — 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: Sharpless 45 Context triple: [Omega Nebula, catalogNumber, Sharpless 45]
-
A.
Caldwell 49
Caldwell 49 is a large, bright emission nebula and star-forming region in the constellation Monoceros, popularly known as the Rosette Nebula.
-
B.
Caldwell 14
Caldwell 14 is an open star cluster in the constellation Perseus, forming part of the famous Double Cluster visible to the naked eye in dark skies.
-
C.
Barnard 5
Barnard 5 is a dark molecular cloud and active star-forming region located within the Perseus molecular cloud complex.
-
D.
IC 4715
IC 4715 is a bright, star-rich region of the Milky Way in the constellation Sagittarius, commonly known as the Small Sagittarius Star Cloud.
-
E.
IC 4665
IC 4665 is a bright, young open star cluster located in the constellation Ophiuchus, visible with binoculars or small telescopes.
- 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: Sharpless 45 Target entity description: Sharpless 45 is an emission nebula in the constellation Sagittarius, better known as the Omega Nebula, notable for its bright star-forming regions and distinctive swan-like shape.
-
A.
Caldwell 49
Caldwell 49 is a large, bright emission nebula and star-forming region in the constellation Monoceros, popularly known as the Rosette Nebula.
-
B.
Caldwell 14
Caldwell 14 is an open star cluster in the constellation Perseus, forming part of the famous Double Cluster visible to the naked eye in dark skies.
-
C.
Barnard 5
Barnard 5 is a dark molecular cloud and active star-forming region located within the Perseus molecular cloud complex.
-
D.
IC 4715
IC 4715 is a bright, star-rich region of the Milky Way in the constellation Sagittarius, commonly known as the Small Sagittarius Star Cloud.
-
E.
IC 4665
IC 4665 is a bright, young open star cluster located in the constellation Ophiuchus, visible with binoculars or small telescopes.
- F. None of above. chosen
Statements (45)
| Predicate | Object |
|---|---|
| instanceOf |
H II region
ⓘ
emission nebula ⓘ |
| alsoKnownAs |
Checkmark Nebula
ⓘ
Horseshoe Nebula ⓘ M17 ⓘ Messier 17 ⓘ NGC 6618 ⓘ Omega Nebula ⓘ Swan Nebula ⓘ |
| angularSize | about 11 arcminutes by 6 arcminutes ⓘ |
| apparentMagnitudeV | approximately 6.0 ⓘ |
| bestSeenFrom |
low northern latitudes
ⓘ
southern latitudes ⓘ |
| bestViewingSeason | northern summer ⓘ |
| catalogCode | Sh 2-45 ⓘ |
| celestialHemisphere | southern celestial hemisphere ⓘ |
| contains |
dark dust lanes
ⓘ
embedded star cluster ⓘ molecular clouds ⓘ young massive stars ⓘ |
| declination | −16° 11′ (approximate) ⓘ |
| discoveredBy | Philippe Loys de Chéseaux ⓘ |
| discoveryYear | 1745–1746 (approximate) ⓘ |
| distanceFromEarth |
about 1.6–2.0 kiloparsecs
ⓘ
about 5000–6000 light-years ⓘ |
| dominantEmissionLine |
H-alpha
ⓘ
[O III] ⓘ |
| excitedBy | ultraviolet radiation from hot O-type stars ⓘ |
| hasColor | reddish due to hydrogen emission ⓘ |
| hasShape |
omega-like shape
ⓘ
swan-like shape ⓘ |
| includedInCatalog |
Messier catalogue
ⓘ
New General Catalogue (NGC) ⓘ
linked to:
New General Catalogue
Sharpless catalog of H II regions ⓘ
linked to:
Sharpless catalogue
|
| isPopularTargetFor |
amateur astrophotography
ⓘ
professional astronomical studies of star formation ⓘ |
| isRegionOf | active star formation ⓘ |
| locatedInConstellation | Sagittarius ⓘ |
| locatedNear | Galactic plane ⓘ |
| observedIn |
infrared wavelengths
ⓘ
optical wavelengths ⓘ radio wavelengths ⓘ |
| partOf |
Milky Way
ⓘ
Sagittarius Arm of the Milky Way ⓘ
linked to:
Sagittarius Arm
|
| rightAscension | 18h 20m (approximate) ⓘ |
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: Sharpless 45 Description of subject: Sharpless 45 is an emission nebula in the constellation Sagittarius, better known as the Omega Nebula, notable for its bright star-forming regions and distinctive swan-like shape.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.