Rotation Fraction
Definition
The Rotation Fraction is the share of a galaxy's stellar kinetic energy in ordered rotation about its axis: above about one half a galaxy is a disk, below it a spheroid.
The game reads each galaxy's type from it and the share of young blue stars: spiral (rotating, forming stars), lenticular (rotating, quiet), elliptical (swarming), irregular, dwarf and starburst.
Formally, κ_rot = K_φ / K, where κ_rot [∅] is the rotation fraction, K_φ [𝕄·𝕃²·𝕋⁻²] the kinetic energy of rotation about the axis and K [𝕄·𝕃²·𝕋⁻²] the whole kinetic energy: [∅] = [∅].
It connects to Galaxy (BPT) and Halo Spin Parameter.
Mathematical Expression
κ_rot = K_φ / K
Technical Details
Category: Manuscript
Chapter: Chapter 3
Importance Level: