Population II

E484154

Population II refers to an older, metal-poor class of stars typically found in globular clusters and the galactic halo, formed early in the history of the universe.

All labels observed (1)

Label Occurrences
Population II canonical 11

How this entity was disambiguated

Statements (49)

Predicate Object
instanceOf astrophysical concept
stellar population
alsoKnownAs Population II stars
characteristicAge old stars
chemicalAbundancePattern enhanced alpha-elements relative to iron
classificationSystem Baade stellar population classification
color generally redder than young massive stars
contrastWith Population I
Population III
discoveredBy Walter Baade
discoveryContext resolution of stellar populations in Andromeda
discoveryEpoch 1940s
formationEpoch early universe
formedAfter Population III stars
formedFrom gas enriched by first generations of stars
foundIn bulge of galaxies
dwarf spheroidal galaxies
galactic halo
globular clusters
old stellar halos of galaxies
heliumContent lower than in younger populations on average
hostOf blue horizontal branch stars
many RR Lyrae variable stars
importance constrains early star formation history
kinematics eccentric orbits
high-velocity orbits
often highly inclined to galactic disk
massRange predominantly low-mass long-lived stars
metallicity metal-poor
metallicityRelativeToSun lower than solar
observationalSignature dominance in globular cluster color-magnitude diagrams
weak metal absorption lines in spectra
relativeAgeToPopulationI older
relativeMetallicityToPopulationI lower
roleInCosmology tracers of early galaxy formation
roleInDistanceScale includes RR Lyrae variables as standard candles
roleInGalacticAstronomy used to study galactic halo structure
spatialDistribution spheroidal
starFormationActivity no ongoing star formation
typicalAgeRange ≈ 10–13 billion years
typicalEnvironment low gas density regions
typicalLocationInMilkyWay Milky Way globular clusters
Milky Way halo
typicalMetallicityRange [Fe/H] ≈ −1 to −3
typicalStellarTypes horizontal branch stars
low-mass main-sequence stars
red giants
usedToInfer age of the Milky Way
chemical evolution of galaxies

How these facts were elicited

Referenced by (11)

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

Messier 28 stellarPopulation Population II
Messier 30 stellarPopulation Population II
Population I youngerThan Population II
Population I metalRicherThan Population II
Messier 10 hasStellarPopulation Population II
GCl 99 galacticPopulation Population II
M75 stellarPopulation Population II
NGC 5286 stellarPopulation Population II
NGC 6712 stellarPopulation Population II
M30 galacticPopulation Population II
Messier 92 stellarPopulation Population II