Abstract
We analyze the dynamics of binary systems with time-dependent mass loss and periastron effect-i.e., a supposed enhanced mass loss during periastron passages-by means of analytical and numerical techniques. In this way, we study the variation of orbital elements in terms of three small parameters, which describe the time-dependent mass loss ( alpha1() , alpha2() ) and the mass loss by periastron effect ( beta ). It is demonstrated that the latter gives rise to secular variations in some orbital elements: eccentricity, semi-major axis and period. Lastly, we suggest that some of the anomalous behavior observed in some close binaries can be explained by taking into account the periastron effect. As a demonstration some practical applications are also included.
