Boson Stars in General Scalar-tensor Gravitation: Equilibrium Conngurations

We study equilibrium conngurations of boson stars in the framework of general scalar-tensor theories of gravitation. We analyse several possible couplings , with acceptable weak eld limit and, when known, nucleosynthesis bounds, in order to work in the cosmologically more realistic cases of this kind of theories. We found that for general scalar-tensor gravitation, the range of masses boson stars might have is comparable with the general rel-ativistic case. We also analyse the possible formation of boson stars along diierent eras of cosmic evolution, allowing for the eeective gravitational constant far out form the star to deviate from its current value. In these cases, we found that the boson stars masses are sensitive to this kind of variations, within a typical few percent. We also study cases in which the coupling is implicitly deened, through the dependence on the radial coordinate, allowing it to have signiicant variations in the radius of the structure.