A model for the double system with the X-ray source Her X-1 is considered. It is supposed that the central star has a sufficiently strong magnetic field for the outflow of the matter to occur in jets. When the neutron star is in the jet the optical depth τx attributable to the X-ray emission due to Compton scattering is greater than unity and the solid angle of the emitted X-radiation is broad, ∼ 180°. In the opposite case, τx < 1, there is a narrow angle of emission and the radiation falls on to the star and is not observed on the Earth. The motion of the neutron star relative to the jet is due to nonsynchronization between the orbital motion and rotation of the central star. If the duration of the whole orbit around the central star is 35 days and the dimension of the jet is about 1/3 of the orbit, then such a model explains features connected with the 35-day cycle.

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Based on the miscellaneous published radio and optical data, SDSS and APM catalogue we consider the various properties of the giant radio sources (gRS) with the aim of refining the conditions leading to the formation of these objects. We compare gRSs with the regular-sized radio sources in radio and optical bands, yielding the following results:1. The fraction of broad line objects among gRSs with high excitation spectrum is the same as for the RSs from isotropic samples. According to "Unified Scheme" this leads to the isotropic angle distribution of gRSs jets, thus gRSs cannot be characterized as objects with jets lying in the plane of sky.2. gRSs do not differ from normal sized RSs in apparent asymmetry distribution of their extended radio components (ERC). However the fact that asymmetry distributions for gRSs and giant radio quasars (gQSS) are essentially the same leads within the Unification Scheme to the conclusion that the origin of this asymmetry is in the non-uniform environment.3. The observed radio jet powers for gRSs and regular RSs are almost the same, so this can hardly explain why gRSs are that large.4. The richness of the environment for gRSs is the same as for normal sized RSs. Host galaxies of gRSs can be either isolated or be a part of a clusters up to Abell Richness Class 1. This contradicts the opinion that the low density of the environment is the single reason for gRSs formation.5. Relatively large fraction of Double-Double radio sources among gRSs presumes their lifetimes larger than normal sized RSs by order of magnitude. This fact and coincidence of gRSs space density with space density of Fanaroff-Riley II RSs in local ( < 0.1) Universe suggest that about 10% of FRII RSs have by order of magnitude longer lifetimes and eventually evolve to gRSs.6. The lack of Double-Double gQSSs can be explained by their shorter active phase in comparison with gRGs. In the alternative (to the unification scheme) evolution scheme, which combines radio-loud QSSs and RGs together, former evolve in time into latter. According to this scheme the observed relative quantity of radio quasars in gRSs population (~0.1) can be interpreted as the presence long-living population of radio loud QSSs as ~10% of all radio quasars. Such population of long-living radio quasars can appear to be the parent population for gRGs 1 bkomberg@asc.rssi.ru 2

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