On Contraction of Stellar System

Stellar systems are included which include the comparable amount of gas with stars. The condition for stellar systems to contract due to the dissipation of its kinetic energy through the direct and gravitational interactions between stars and gases is obtained. For a stellar system to contract within a Hubble time, it must be compact initially, and accordingly, the gas density is high. The gas carmot remain interstellar for a Hubble time and the stellar system does not contract unless the system is extremely compact initially. In conclusion, it is impossible for a stellar system to contract from the stage where the dissipation of stellar kinetic energy is ineffective to the stage where it is effective. (auth)