| As one of the four great discoveries of radio astronomy in 1960s, pulsar makes us to observe a star supported by neutron degeneracy pressure, i.e. neutron star, an-ticipated by Landau for the first time. Limited the ability of current telescopes, pulsar is almost the unique way through which we could see a neutron star (NS). From the first pulsar discovered at the end of 1967, there are more than 2000 pulsars have been detected to date, from radio band to X-ray or even y-ray. The spin periods Ps are dis-tributed from about 1 ms to almost 12 s, and are constituted by two main groups. The first group are normal pulsars with Ps～0.5 s, and another group are named millisec-ond pulsars(MSPs) with Ps～3 ms. In the standard recycling scenario, a dead pulsar can spin up during the low-mass X-ray binary (LMXB) phase, through the accretion of mass and angular momentum from its companion, and a newborn MSP would appear after the termination of mass transfer. For a long time, such a MSP recycling model is supported by many observations and widely accepted. Recently, several transitional pulsars swinging between accretion-powered X-ray pulsars and rotation-powered radio pulsars bring us a unique way to witness the final phase of recycling scenario. Neverthe-less, there are many questions in details on the evolution of LMXBs and the formation of MSPs, concluding the birthrate problem between MSPs and their LMXB progeni-tors. In fact, the observed MSP companions could be main sequence stars, He white dwarfs (WDs), CO WDs, NSs, planets and so on, almost all the main celestial bodies. And if the theoretical products of binary evolution could reproduce them in distribution of orbital periods and companion mass is still not very clear. Besides, a considerable part (-1/3) of MSPs are not posited in binary systems, they are isolated MSPs, and their origin, recycling or other channel is also unknown. Base on these considerations above, we would to investigate the evolution of LMXBs with different initial models and various physical process, and pay close attention to their final products. Then com-pare our results with observational data, try to resolve some of the questions above, or to modify our model to fit the observation.In Chapter one, we would give a survey of X-ray binary and pulsar, from the discoveries to their characteristics, classification, distribution and so on.In Chapter two, there’s a brief introduction of the LMXB evolution, from the the-oretical point of view, specially on the formation of LMXBs, the evolution of a single star, the modelling of a primordial LMXB and the main physical process in evolution, and finally the accretion process and spin evolution of NSs.In Chapter three, we would discuss the formation of compact MSP-He WD bina-ries combining our own work. Specially we are interested in the compact systems with orbital period less than 1 day, and calculate the theoretical relation between orbital pe-riod Pf and the companion WD mass MWD with various initial parameters. And apply our results to explain the formation histories of two special systems PSRs J0348+0432 and J1738+0333.In Chapter four, we would pay more attention the particular redback MSPs which are evaporating their companions with radio eclipse observed by us. Among these redbacks, there are several transitional MSPs switch between rotation-powered radio pulsars and accretion-powered X-ray pulsars, which bring us the most direct evidence of recycling scenario. We would firstly give a brief review of current models on the formation of redbacks and the possible problems within them. Then we would propose our own model, where we suggest redbacks may form during quiescence of transient LMXBs under disk instability.In Chapter five, we would continue the work of Chapter four, introduce the evap-oration winds of the companion star under MSP irradiation. Our calculation results indicate that the evaporation effects can significantly affect the secular evolutionary tracks of standard LMXBs, and the final products may outlie the standard prediction. Also, we find the dynamical unstable mass transfer can take place when the companion mass drop below about a Jupiter mass, under the evaporation winds, which can open a possible and wide channel to form isolated MSPs. Need to be pointed out, these results above heavily depend on the winds scale and the corresponding angular momentum loss, both of which are less limited and deserved to further investigation.The final Chapter six is a brief summary of this paper and a prospect to future study. |
