Abell 21
E1497928
UNEXPLORED
Abell 21 is a large, faint planetary nebula in the constellation Gemini, commonly known as the Medusa Nebula.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Abell 21 canonical | 2 |
How this entity was disambiguated
This entity first appeared as the object of triple T21720301 — 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: Abell 21 Context triple: [Medusa Nebula, hasAlternativeName, Abell 21]
-
A.
Abell 2151
Abell 2151 is a rich, nearby galaxy cluster located in the constellation Hercules, notable for its high fraction of spiral galaxies and active galaxy interactions.
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B.
Abell 262
Abell 262 is a nearby galaxy cluster in the constellation Andromeda, notable for its relatively low mass and cool-core intracluster medium within the Perseus–Pisces Supercluster.
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C.
Abell 2142
Abell 2142 is a massive, X-ray-bright galaxy cluster known for being one of the largest and most studied examples of cluster mergers in the universe.
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D.
Hercules Cluster (Abell 2151)
Hercules Cluster (Abell 2151) is a nearby, irregularly shaped galaxy cluster rich in spiral galaxies and active interactions, located in the constellation Hercules.
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E.
Abell 426
Abell 426, also known as the Perseus Cluster, is a massive, nearby galaxy cluster notable for its bright X-ray emission and central active galaxy NGC 1275.
- 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: Abell 21 Target entity description: Abell 21 is a large, faint planetary nebula in the constellation Gemini, commonly known as the Medusa Nebula.
-
A.
Abell 2151
Abell 2151 is a rich, nearby galaxy cluster located in the constellation Hercules, notable for its high fraction of spiral galaxies and active galaxy interactions.
-
B.
Abell 262
Abell 262 is a nearby galaxy cluster in the constellation Andromeda, notable for its relatively low mass and cool-core intracluster medium within the Perseus–Pisces Supercluster.
-
C.
Abell 2142
Abell 2142 is a massive, X-ray-bright galaxy cluster known for being one of the largest and most studied examples of cluster mergers in the universe.
-
D.
Hercules Cluster (Abell 2151)
Hercules Cluster (Abell 2151) is a nearby, irregularly shaped galaxy cluster rich in spiral galaxies and active interactions, located in the constellation Hercules.
-
E.
Abell 426
Abell 426, also known as the Perseus Cluster, is a massive, nearby galaxy cluster notable for its bright X-ray emission and central active galaxy NGC 1275.
- F. None of above. chosen
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.