Variable infrared radiation from x-ray sources 4U 0115+634 and A 0535+262

Data are presented which indicate that the IR excess in radiation from the X-ray binaries 4U 0115 + 634 and A 0535 + 262 is produced in the accreting flow of matter in the vicinity of neutron stars. It is likely that IR radiation from X-ray binaries consists of two components, namely the free-free radiation from an electron envelope surrounding the optical component, and a nonthermal, coherent radiation which may be generated in an accreting flow of matter near the neutron star. The maser mechanism at proton gyrofrequencies is noted as a possible IR generation mechanism.