  In this paper, we use the restricted three body problem in the binary stellar
systems, taking photogravitational effects of both the stars. The aim of this
study is to investigate the motion of the infinitesimal mass in the vicinity of
the Lagrangian points. We have computed semi-analytical expressions for the
locations of the collinear points with the help of the perturbation technique.
The stability of the triangular points is studied in stellar binary systems
Kepler-34, Kepler-35, Kepler-413 and Kepler-16. To investigate the stability of
the triangular points, we have obtained the expressions for critical mass which
depends on the radiation of both primaries. Fourier-series method is applied to
obtain periodic orbits of the infinitesimal mass around triangular points in
binary stellar systems. We have obtained Fourier expansions of the periodic
orbits around triangular points upto third order terms. A comparison is made
between periodic orbits obtained by Fourier-series method and with Runge-Kutta
integration of fourth order.
