Messier 20
E106312
Messier 20, also known as the Trifid Nebula, is a bright, star-forming emission and reflection nebula famous for its striking three-lobed appearance.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Messier 20 canonical | 2 |
| M20 (Trifid Nebula) | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T869227 — 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: Messier 20 Context triple: [Sagittarius, contains, Messier 20]
-
A.
Messier 17
Messier 17, also known as the Omega or Swan Nebula, is a bright star-forming emission nebula located in the constellation Sagittarius.
-
B.
NGC 6822
NGC 6822 is a barred irregular dwarf galaxy located in the constellation Sagittarius and is one of the nearest and best-studied galaxies outside the Milky Way.
-
C.
Messier 8
Messier 8, also known as the Lagoon Nebula, is a large, bright emission nebula and active star-forming region visible in the constellation Sagittarius.
-
D.
Open cluster M25
Open cluster M25 is a bright, relatively nearby star cluster in the constellation Sagittarius, visible with binoculars and often studied as a young stellar grouping within the Milky Way.
-
E.
Messier
Messier is a French-origin surname most famously associated with Canadian ice hockey legend Mark Messier.
- 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: Messier 20 Target entity description: Messier 20, also known as the Trifid Nebula, is a bright, star-forming emission and reflection nebula famous for its striking three-lobed appearance.
-
A.
Messier 17
Messier 17, also known as the Omega or Swan Nebula, is a bright star-forming emission nebula located in the constellation Sagittarius.
-
B.
NGC 6822
NGC 6822 is a barred irregular dwarf galaxy located in the constellation Sagittarius and is one of the nearest and best-studied galaxies outside the Milky Way.
-
C.
Messier 8
Messier 8, also known as the Lagoon Nebula, is a large, bright emission nebula and active star-forming region visible in the constellation Sagittarius.
-
D.
Open cluster M25
Open cluster M25 is a bright, relatively nearby star cluster in the constellation Sagittarius, visible with binoculars and often studied as a young stellar grouping within the Milky Way.
-
E.
Messier
Messier is a French-origin surname most famously associated with Canadian ice hockey legend Mark Messier.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
H II region
ⓘ
Messier object ⓘ NGC object ⓘ emission nebula ⓘ reflection nebula ⓘ star-forming region ⓘ |
| alsoKnownAs |
M20
ⓘ
NGC 6514 ⓘ Trifid Nebula ⓘ |
| angularSize | 28 arcminutes × 28 arcminutes ⓘ |
| apparentMagnitudeV | 9.0 ⓘ |
| belongsToCatalog |
Messier catalogue
ⓘ
surface form:
Messier Catalogue
New General Catalogue ⓘ |
| bestSeenFrom | Southern Hemisphere ⓘ |
| bestSeenInMonth | July ⓘ |
| catalogCode |
M20
ⓘ
NGC 6514 ⓘ |
| contains |
Herbig–Haro objects
ⓘ
molecular clouds ⓘ protostars ⓘ young massive stars ⓘ |
| declination | −23° 02′ ⓘ |
| discoveredBy | Charles Messier ⓘ |
| discoveryDate | 1764 ⓘ |
| distanceFromEarth |
approximately 1.25 kiloparsecs
ⓘ
approximately 4100 light-years ⓘ |
| dominantEmissionLine | H-alpha ⓘ |
| hasColor |
blue reflection regions
ⓘ
red emission regions ⓘ |
| hasComponent |
dark nebula lanes
ⓘ
emission nebula region ⓘ open star cluster ⓘ reflection nebula region ⓘ |
| isRegionOf | active star formation ⓘ |
| locatedIn |
Sagittarius Arm
ⓘ
surface form:
Sagittarius Arm of the Milky Way
|
| locatedInConstellation | Sagittarius ⓘ |
| nearObjectOnSky |
Lagoon Nebula
ⓘ
Messier 21 ⓘ |
| notableFeature |
bright central star cluster
ⓘ
dark dust lanes dividing the nebula ⓘ three-lobed appearance ⓘ |
| observedBy | Hubble Space Telescope ⓘ |
| partOf | Milky Way ⓘ |
| rightAscension | 18h 02m ⓘ |
| spectralTypeOfIonizingStars |
B-type
ⓘ
O-type ⓘ |
| visibleIn |
infrared wavelengths
ⓘ
optical wavelengths ⓘ radio wavelengths ⓘ |
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: Messier 20 Description of subject: Messier 20, also known as the Trifid Nebula, is a bright, star-forming emission and reflection nebula famous for its striking three-lobed appearance.
Referenced by (3)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
M20 (Trifid Nebula)