Cosmological constant, conical defect and classical tests of general relativity

We investigate the perihelion shift of the planetary motion and the bending of starlight in the Schwarzschild field modified by the presence of a A-term plus a conical defect. This analysis generalizes an earlier result obtained by Islam (Phys. Lett. A 97, 239, 1983) to the case of a pure cosmological constant. By using the experimental data we obtain that the parameter is an element of characterizing the conical defect is less than 10(-9) and 10(-7), respectively, on the length scales associated with such phenomena. In particular, if the defect is generated by a cosmic string, these values correspond to Emits on the linear mass densities of 10(19) g/cm and 10(21) g/cm, respectively.