Formation Of Accreting Millisecond X-ray Pulsars

Accreting millisecond X-ray pulsars(AMXPs)are an important subclass of lowmass X-ray binaries(LMXBs),in which coherent millisecond X-ray pulsations can be observed during outburst states.They have dual characteristics of LMXBs and millisecond pulsars(MSPs),providing a direct confirmation for the recycling scenario.Moreover,AMXPs are also important for the studies of accretion physics of compact binaries and physical properties of neutron stars.However,their formation and evolution are not well understood.In this thesis,we simulate the evolution of LMXBs with the MESA code.Based on the binary evolutionary model of LMXBs and the model of accretion disk instability,we explore the formation and evolution of AMXPs.By comparing our results with the observed properties of AMXPs,we obtain the following conclusions.(1)Most of the observed AMXPs are likely produced from LMXBs with orbital periods at the onset of Roche lobe overflow close to the bifurcation period.Meanwhile,the accretion disk instability may play an important role in the formation of most AMXPs.(2)The AMXPs with main sequence(MS)donors ultimately evolve into AMXPs with extremely lowmass He WD donors.(3)Our results indicate that these AMXPs with MS donors are likely to have donor stars near the terminal-age main sequence.