- What are "kinematics?"
- Kinematics are the way that kinematic energy (velocities) is distributed
among stars in a sample. The average velocity of stars and the dispersion
of velocities in a sample tell us about the motion of this sample as well as
their spatial distribution if placed in a gravitational potential. So the
average velocity of stars in the disk of the galaxy tell us how fast it is
rotating and since the disk of the galaxy has a gravitational potential,
we can calculate how far the disk stars are spread from the galactic plane
by their velocity dispersion perpendicular to the plane of the galaxy.
Back to the RR Lyrae Project Page.