Normalisation at the Triangular Equilibria in The Doubly Photogravitational Restricted Problem

In order to study the stability in the sense of Lyapunov of the triangular equilibria L₄ and L₅ in the circular restricted problem of three bodies when both finite masses are radiating, the normalization of the second order terms of the Hamiltonians has been done. Special attention is paid to the problem of determining the curves in the parameter plane along which the system presents resonances of the type (1:1), (1:2) and (1:3).