Positron annihilation fluxes, light curves and spectra from misaligned microquasars

We consider nearby misaligned microquasars, where the jets are inclined substantially enough toward the plane of orbit to make them occasionally hit the atmosphere of the companion star. Assuming that microquasar jets do eject substantial quantities of positrons (see Guessoum, Jean, and Prantzos, this workshop [6]), these systems would represent interesting annihilation point sources, for which we determine the resulting flux and the corresponding light curve, as well as the line's spectral profile. For these calculations, a detailed treatment of the physical processes undergone by the positrons in the atmosphere of the companion star is performed. We discuss the possibility of detection of such point sources by future instruments.