The Contraction of an Isolated Mono-component System

<正> A mono-component spherical system has been studied under various initial conditions,and an analytic representative p(r= 0,t) = p0(1-(D,t)2) of the density at the center of the system has beenfound under the condition that the initial radius of the system r0>Dr The theoretical characteristic constants,the critical radius Dr-1=(3kT/4πm2n0G)1/2 and the gestation Dr-1=(3/4πmn0G)1/2exp(l:24),are dependent on the initial density p0=mn0t and the initial absolute temperature T at the center of the system These theoretical values accord with the corresponding values of astronomy.These results are helpful lor solving the problem of how stars were formed in the universe.