openCluster Stephenson 2
E459137
Stephenson 2 is a massive, heavily reddened open star cluster rich in red supergiants, located in the direction of the constellation Scutum.
All labels observed (3)
| Label | Occurrences |
|---|---|
| open cluster Stephenson 2 | 1 |
| openCluster Stephenson 2 canonical | 1 |
| rich red supergiant cluster Stephenson 2 | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T4619163 — 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: openCluster Stephenson 2 Context triple: [Scutum, contains, openCluster Stephenson 2]
-
A.
Jewel Box cluster
The Jewel Box cluster is a bright and colorful open star cluster in the constellation Crux, renowned for its striking mix of blue and red stars visible even in small telescopes.
-
B.
open cluster NGC 2244
Open cluster NGC 2244 is a young, bright star cluster whose hot, massive stars illuminate and sculpt the surrounding Rosette Nebula in the constellation Monoceros.
-
C.
Beti-Fang cluster
The Beti-Fang cluster is a group of closely related Bantu languages spoken primarily in Cameroon, Equatorial Guinea, and neighboring Central African regions.
-
D.
Collinder 228
Collinder 228 is an open star cluster embedded in the Carina Nebula, notable for its young, massive stars that help illuminate and shape the surrounding gas and dust.
-
E.
Sharpless 2-275
Sharpless 2-275 is a large, circular emission nebula in the constellation Monoceros, notable for its active star-forming region and striking rose-like appearance.
- 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: openCluster Stephenson 2 Target entity description: Stephenson 2 is a massive, heavily reddened open star cluster rich in red supergiants, located in the direction of the constellation Scutum.
-
A.
Jewel Box cluster
The Jewel Box cluster is a bright and colorful open star cluster in the constellation Crux, renowned for its striking mix of blue and red stars visible even in small telescopes.
-
B.
open cluster NGC 2244
Open cluster NGC 2244 is a young, bright star cluster whose hot, massive stars illuminate and sculpt the surrounding Rosette Nebula in the constellation Monoceros.
-
C.
Beti-Fang cluster
The Beti-Fang cluster is a group of closely related Bantu languages spoken primarily in Cameroon, Equatorial Guinea, and neighboring Central African regions.
-
D.
Collinder 228
Collinder 228 is an open star cluster embedded in the Carina Nebula, notable for its young, massive stars that help illuminate and shape the surrounding gas and dust.
-
E.
Sharpless 2-275
Sharpless 2-275 is a large, circular emission nebula in the constellation Monoceros, notable for its active star-forming region and striking rose-like appearance.
- F. None of above. chosen
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
astronomical object
ⓘ
open star cluster ⓘ stellar cluster ⓘ |
| belongsTo | Galactic disk ⓘ |
| discoveredBy | Charles Bruce Stephenson ⓘ |
| hasAge | about 17 million years ⓘ |
| hasAgeRange | 10–20 million years ⓘ |
| hasAlternativeName |
RSGC2
ⓘ
linked to:
RSGC2-18
Red Supergiant Cluster 2 ⓘ |
| hasApparentMagnitude | about 14 (V band, integrated; heavily reddened) ⓘ |
| hasClusterRadius | a few parsecs ⓘ |
| hasClusterType | young massive open cluster ⓘ |
| hasCoreRadius | about 1 parsec (order of magnitude) ⓘ |
| hasDeclination | −06° (approximate, J2000) ⓘ |
| hasDiscoveryMethod | infrared survey identification ⓘ |
| hasDistanceFromEarth |
about 19,500 light-years
ⓘ
about 6 kiloparsecs ⓘ |
| hasDominantStellarType |
B-type main-sequence progenitors (earlier evolutionary stage)
ⓘ
red supergiant stars ⓘ |
| hasEstimatedInitialMassOfRedSupergiants | about 10–20 solar masses ⓘ |
| hasEstimatedMass | several 10^4 solar masses ⓘ |
| hasGalacticLatitude | about 0 degrees ⓘ |
| hasGalacticLongitude | about 26 degrees ⓘ |
| hasHighInterstellarExtinction | true ⓘ |
| hasMetallicity | approximately solar or slightly supersolar (inner Galaxy environment) ⓘ |
| hasNumberOfRedSupergiants |
more than 20
ⓘ
one of the largest known concentrations of red supergiants in the Milky Way ⓘ |
| hasRedSupergiantSpectralTypes | K–M supergiants ⓘ |
| hasRightAscension | 18h 39m (approximate, J2000) ⓘ |
| hasScientificInterest | benchmark for red supergiant cluster population in the Milky Way ⓘ |
| hasSpectralStudiesIn | near-infrared spectroscopy ⓘ |
| hasStellarPopulationType | young massive stars ⓘ |
| isBestObservedIn | infrared wavelengths ⓘ |
| isDifficultToObserveInVisible | true ⓘ |
| isHeavilyReddened | true ⓘ |
| isMassiveCluster | true ⓘ |
| isPartOf | group of red supergiant clusters near Scutum ⓘ |
| isRichIn | red supergiants ⓘ |
| isSimilarTo |
RSGC1
ⓘ
RSGC3 ⓘ |
| isUsedToStudy |
late stages of massive star evolution
ⓘ
massive cluster formation in the inner Milky Way ⓘ red supergiant properties ⓘ |
| liesIn |
Milky Way galaxy
ⓘ
linked to:
Milky Way
Scutum–Crux arm region ⓘ
linked to:
Scutum–Centaurus Arm
inner Galaxy ⓘ |
| locatedInConstellation | Scutum ⓘ |
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: openCluster Stephenson 2 Description of subject: Stephenson 2 is a massive, heavily reddened open star cluster rich in red supergiants, located in the direction of the constellation Scutum.
Referenced by (3)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject linked to:
redSupergiant Stephenson 2-18
linked to: openCluster Stephenson 2
subject linked to:
redSupergiant Stephenson 2-18
linked to: openCluster Stephenson 2