Statistical estimates and physics of close bynary systems (C.B.S.) of neutron stars

After some statistical considerations about the number of C.B.S.s with one neutron star in our galaxy, we study the possible kinds of emission of C.B.S.s with two neutron stars. Section 2 contains considerations on the dimension of such a system at the moment of its formation. From the comparison of different kinds of power emitted we deduce that the orbital gravitational emission $P_{go}$ dominates. The dynamical evolution of the orbital elements $a$ and $e$ is determined by $P_{go}$ and by tidal friction, which produce opposite effects. The quantitative comparison between $P_{go}$ and $P_{tf}$ (work made per unit time by tidal torque) says that $P_{go}>P_{tf}$. Therefore we conclude that it is $a<0$ and $e<0$; that is the evolution of the systems is towards the collapse.