  We consider the gas dynamics in an accreting binary system of degenerate
stars within the framework of the Newtonian approximation. In such a system,
the accretion stream can impact the surface of a white dwarf (WD) or neutron
star (NS) as a result of the very compact orbit. This causes a loss of angular
momentumfrom the orbit and spin-up of the accretor. We construct approximations
for the specific angular momentum of the accreting matter which goes to spin up
the accretor and some other parameters of the system. It is shown that the
obtained approximation of the specific momentum is qualitatively different from
the widely used Keplerian formula. It should affect the boundary between
scenarios of immediate tidal disruption and slow mass loss of the donor in
WD-WD and NS-NS binaries, as well as the time of stable mass transfer in the
stripping scenario.
