ИСТИНА

Recently, three long-period radio sources have been discovered: PSR J0901-4046, GLEAM-X J1627-52, and GPM J1839-10. We model their magneto-rotational evolution and discuss their possible origin in binary systems. In the framework of standard scenarios, it is often accepted that the pulsar mechanism is switched off when an external matter can penetrate the light cylinder. If the matter is stopped outside the light cylinder then the neutron star is at the ejector stage. We demonstrate that for realistic parameters of the interstellar medium, the 76-second pulsar PSR J0901-4046 might be at this stage. However, sources GLEAM-X J1627-52 and GPM J1839-10 with periods >1000 s can be ejectors only in the case of unrealistically large dipolar fields >1016 G. Also, we show that neutron stars with spin periods ˜100 s and dipolar magnetic fields <1013 G cannot be ejectors in a typical interstellar medium. Thus, we predict that long-period pulsars with standard fields will not be discovered. Our calculations demonstrate that for realistically rapid spin-down during the propeller stage, isolated neutron stars with velocities <100 km/s and assumed long initial spin periods can reach the stage of accretion from the interstellar medium within at most a few billion years as they are born already at the propeller stage or sufficiently close to the critical period of the ejector-propeller transition. If neutron stars with long initial spin periods form a relatively large fraction of all Galactic neutron stars then the number of isolated accretors is substantially larger than it has been predicted by previous studies. Finally, we use a population synthesis of binary stars to test the hypothesis that long-period neutron stars can be born in binary systems destroyed after the second supernova explosion. Then, the neutron stars actually are not young (their characteristic ages do not correspond to their physical ages) and their spin periods were influenced by accretion in binaries. We calculate the formation rate of such neutron stars which appears to be about 1% of the radio pulsar birth rate. Thus, potentially some long-period radio transients can be related to disrupted binaries, but the probability for this is rather low. Also, there are important uncertainties in neutron star spin periods after their intensive interactions with their companions.