Accretion efficiency and mass transfer in two binary star systems

We analyze the accretion properties of two binary star systems: the BY Draconis type variable V1803 Cyg, which is an A component of the binary system 61 Cyg and the semi-regular (SR) symbiotic variable NQ Gem. In this aim, we estimate an accretion efficiency in these binaries, based on the relation between luminosity and a rate of accretion. We give assumptions on the currently active mass transfer mechanism between the components in the binaries. This could be relevant to define the type of accretion, wind or disc is dominant for each of the objects. We compare the results for both objects, according to the features of their different stellar types. We appraise the possibilities for the transitions between the accretion regimes in the processes of evolution of the studied objects.