The Virial Theorem
• In a system of N particles, gravitational
forces tend to pull the
system together and the stellar
velocities tend to make it fly
apart. It is possible to relate kinetic
and potential energy of a
system through the change of its
moment of intertia
• In a steady-state system, these
tendencies are balanced, which is
expressed quantitatively through
the the Virial Theorem.
• A system that is not in balance
will tend to move towards its virialized
state. (see fig. 4.19 in the
textbook)