redSupergiant Stephenson 2-18

E459136

Stephenson 2-18 is an extremely luminous red supergiant star, considered one of the largest known stars in the Milky Way.

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All labels observed (1)

Label Occurrences
redSupergiant Stephenson 2-18 canonical 1

Statements (44)

Predicate Object
instanceOf cool supergiant
luminous supergiant
red supergiant star
star
discoveredBy Charles Bruce Stephenson NERFINISHED
discoveryMethod infrared survey
hasAlternativeName RSGC2-18 NERFINISHED
St2-18 NERFINISHED
Stephenson 2 DFK 49 NERFINISHED
hasApparentMagnitude very faint in visible light
hasApproximateDistanceFromEarth about 19,000 light-years
about 6 kiloparsecs
hasApproximateLuminosity hundreds of thousands of times the luminosity of the Sun
hasApproximateRadius over 2000 times the radius of the Sun
over 9 astronomical units
hasColor red
hasEffectiveTemperature approximately 3200 K
hasEstimatedInitialMass tens of solar masses
hasEvolutionaryStage late stage massive star
hasExtendedStellarAtmosphere true
hasGalacticEnvironment highly reddened region
hasGalacticLocation inner Milky Way disk
hasHighInfraredBrightness true
hasHighMassLossRate true
hasLuminosityClass Ia
hasOuterLayers cool extended envelope
hasResearchInterest late stages of massive stars
mass loss in red supergiants
massive star evolution
hasSpectralClass M6
hasSpectralType M-type
hasStellarPopulation Population I
hasStellarWind dense slow stellar wind
hasVariability suspected semiregular variability
isAmong largest known stars
most luminous red supergiants
isEmbeddedIn rich red supergiant cluster Stephenson 2 NERFINISHED
isObscuredBy interstellar dust
isUsedAs example of extreme red supergiant
example of extreme stellar radius
locatedIn Milky Way
constellation Scutum NERFINISHED
memberOf open cluster Stephenson 2 NERFINISHED
willEndAs core-collapse supernova

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: redSupergiant Stephenson 2-18
Description of subject: Stephenson 2-18 is an extremely luminous red supergiant star, considered one of the largest known stars in the Milky Way.

Referenced by (1)

Full triples — surface form annotated when it differs from this entity's canonical label.

Scutum contains redSupergiant Stephenson 2-18