Galactic thick disk
E581534
The Galactic thick disk is an older, kinematically hotter, and more metal-poor stellar component of the Milky Way that extends farther above and below the Galactic plane than the thin disk.
Statements (46)
| Predicate | Object |
|---|---|
| instanceOf |
Galactic structural component
ⓘ
stellar population component ⓘ |
| alsoKnownAs | thick disk of the Milky Way NERFINISHED ⓘ |
| containsStars |
old F, G, and K dwarfs
ⓘ
old subgiants and giants ⓘ |
| distinguishedFrom |
Galactic stellar halo
ⓘ
Galactic thin disk NERFINISHED ⓘ |
| extendsAboveBelowPlane | farther than thin disk ⓘ |
| hasAlphaEnhancement | [α/Fe] enhanced relative to thin disk ⓘ |
| hasChemicalSignature | higher [α/Fe] at given [Fe/H] than thin disk ⓘ |
| hasDustContent | less dust than thin disk ⓘ |
| hasFormationScenarios |
accretion of satellite galaxies
ⓘ
heating of early thin disk by mergers ⓘ in-situ formation in turbulent early disk ⓘ radial migration of stars ⓘ |
| hasGasContent | little cold gas at present ⓘ |
| hasGeometry | flattened, disk-like distribution ⓘ |
| hasKinematics | kinematically hotter than thin disk ⓘ |
| hasLocalDensityContribution | significant fraction of local old stars ⓘ |
| hasMassFraction | smaller total mass than thin disk ⓘ |
| hasMeanMetallicity | around [Fe/H] ≈ −0.6 ⓘ |
| hasMetallicity | more metal-poor than thin disk ⓘ |
| hasMetallicityRange | approximately [Fe/H] ≈ −1.0 to −0.3 ⓘ |
| hasRadialExtent | extends several kiloparsecs from Galactic center ⓘ |
| hasRotationalLag |
lag of roughly 30–50 km/s relative to local standard of rest
ⓘ
rotates more slowly than thin disk ⓘ |
| hasScaleHeight | about 0.8–1.5 kiloparsecs ⓘ |
| hasScaleLength | about 2–4 kiloparsecs ⓘ |
| hasStarFormationHistory | dominant star formation early in Milky Way history ⓘ |
| hasStellarPopulationAge | older than thin disk ⓘ |
| hasSurfaceBrightness | lower than thin disk ⓘ |
| hasTypicalAge | about 8–12 billion years ⓘ |
| hasVelocityDispersion | larger than thin disk ⓘ |
| hasVerticalAsymmetry | approximately symmetric above and below plane ⓘ |
| hasVerticalVelocityDispersion | about 40–60 km/s ⓘ |
| identifiedBy |
chemical abundance patterns
ⓘ
kinematic properties of stars ⓘ vertical distribution of stars ⓘ |
| isImportantFor |
constraining Milky Way formation history
ⓘ
testing models of galaxy evolution ⓘ |
| isStudiedIn | Galactic archaeology NERFINISHED ⓘ |
| isStudiedUsing |
Gaia astrometric data
ⓘ
spectroscopic abundance surveys ⓘ stellar kinematics surveys ⓘ |
| isSymmetricAbout | Galactic midplane ⓘ |
| partOf | Milky Way NERFINISHED ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.