A large fraction of stars in binary systems are expected to undergo mass and angular momentum exchange at some point in their evolution , which can drastically alter the chemical and dynamical properties and fates of the systems .
Interaction by stellar wind is an important process in wide binaries .
However , the details of wind mass transfer are still not well understood .
We perform three-dimensional hydrodynamical simulations of wind mass transfer in binary systems to explore mass accretion efficiencies and geometries of mass outflows , for a range of mass ratios from 0.05 to 1.0 .
In particular , we focus on the case of a free wind , in which some physical mechanism accelerates the expelled wind material balancing the gravity of the mass-losing star with the wind velocity comparable to the orbital velocity of the system .
We find that the mass accretion efficiency and accreted specific angular momentum increase with the mass ratio of the system .
For an adiabatic wind , we obtain that the accretion efficiency onto the secondary star varies from about 0.1 % to 8 % for mass ratios between 0.05 and 1.0 .