Spin up and hot spots can drive mass out of a binary

During a short, violent phase of Roche Lobe Overflow (RLOF) in a binary, the gainer can be incapable of accreting all matter lost by the donor. Enhanced rotational velocity caused by spin-up of the gainer combined with accretion luminosity, resulting from the concentration of RLOF-material in an equatorial hot spot, drives matter from the system. The development of a non-conservative phase depends on the initial parameters of the system. Low mass binaries never achieve high enough mass transfer rates, and hence do not lose mass. In intermediate mass binaries matter will be blown away by the gainer during a short era. We have calculated the evolution of binaries with a nine solar mass primary at birth over a wide range of initial orbital periods and mass ratios. We find systems with non-conservatism lasting for the short era of rapid RLOF, during which up to 20% of the system mass is blown into the interstellar medium.