Oort constants
E471607
The Oort constants are two parameters in galactic astronomy that quantify the local rotational properties of the Milky Way near the Sun, particularly its differential rotation.
Observed surface forms (2)
| Surface form | Occurrences |
|---|---|
| Oort constant A | 0 |
| Oort constant B | 0 |
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
Oort constant
ⓘ
Oort constant ⓘ astronomical constant set ⓘ galactic dynamics parameter ⓘ |
| appliesTo |
solar neighborhood
ⓘ
thin disk stars near the Sun ⓘ |
| assumes |
approximate axisymmetry of the Galactic disk
ⓘ
small region around the Sun ⓘ |
| category |
Milky Way structure
NERFINISHED
ⓘ
astrophysical constants ⓘ |
| dependsOn | Galactocentric distance of the Sun ⓘ |
| expressedIn | kilometers per second per kiloparsec ⓘ |
| field |
astrophysics
ⓘ
galactic dynamics ⓘ |
| frameOfReference | local standard of rest ⓘ |
| hasMember |
Oort constant A
NERFINISHED
ⓘ
Oort constant B NERFINISHED ⓘ |
| introducedBy | Jan Oort NERFINISHED ⓘ |
| mathematicallyRelatedTo | derivative of angular rotation speed with respect to Galactocentric radius ⓘ |
| namedAfter | Jan Oort NERFINISHED ⓘ |
| quantifies |
local shear of galactic rotation
ⓘ
local vorticity of galactic rotation ⓘ |
| quantify |
differential rotation near the Sun
ⓘ
local rotational properties of the Milky Way ⓘ |
| relatedTo |
angular velocity of galactic rotation
ⓘ
circular velocity of the Milky Way ⓘ epicyclic approximation ⓘ epicyclic frequency ⓘ galactic rotation curve ⓘ shear of galactic rotation ⓘ vorticity of galactic rotation ⓘ |
| sign |
negative in the Milky Way near the Sun
ⓘ
positive in the Milky Way near the Sun ⓘ |
| symbolForMember |
A
ⓘ
B ⓘ |
| typicalValueApprox |
-12 km/s/kpc
ⓘ
15 km/s/kpc ⓘ |
| usedFor |
constraining the local shape of the Milky Way rotation curve
ⓘ
converting observed stellar proper motions to galactic rotation parameters ⓘ determining local galactic shear ⓘ determining local galactic vorticity ⓘ estimating Milky Way mass distribution near the Sun ⓘ modeling stellar motions in the solar neighborhood ⓘ testing axisymmetric models of the Milky Way ⓘ |
| usedIn |
Milky Way kinematics
ⓘ
galactic astronomy ⓘ galactic rotation studies ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.