... These are the systems which contain compact components of different nature, white dwarf, neutron star or black hole. ... Pulsar appears during X-ray outbursts, but it does not manifest itself in the quiet state (Be stars, BQ Cam, V490 Cep); -falling of low -mass bodies on a compact object due to gravitational capture (a comet nucleus or a meteoroid ) in the detached system (V934 Her, V4641 Sgr). ... B1V-B2Ve star + neutron star & pulsar on the 20.85-day orbit Cep X-4 (ROSAT/PSPC) 1993 . ... 1000/ . ...