On the angular momentum transfer on to compact stars in binary systems

Results of three-dimensional numerical simulations of the gas transfer in c lose binary systems show that, in addition to the formation of a tidally in duced spiral shock wave, it is also possible for accretion streams to be pr oduced, having low specific angular momentum in a region close to the accre ting star. These streams are mainly placed above the orbital disc but are a lso unevenly present in the equatorial plane. The relevance of such flows i s related to formation of hot coronae or bulges in regions very close to th e accretor centre. The eventual formation of such bulges and shock-heated f lows is interesting in the context of advection-dominated solutions and for the explanation of spectral properties of the black hole candidates in bin ary systems.