On the progenitors of millisecond pulsars by the recycling evolutionary channel

Abstract

The recycling model suggested that low‐mass X‐ray binaries (LMXBs) could evolve into binary millisecond pulsars (BMSPs). In this work, we attempt to investigate the progenitor properties of BMSPs formed by the recycling evolutionary channel, and if submillisecond pulsars can be produced by this channel. Using Eggleton’s stellar evolution code, considering that the dead pulsars can be spun up to a short spin period by the accreting material and angular momentum from the donor star, we have calculated the evolution of close binaries consisting of a neutron star (NS) and a low‐mass main‐sequence donor star, and the spin evolution of NSs. In the calculation, some physical processes, such as the thermal and viscous instability of an accretion disc, propeller effect and magnetic braking, are included. Our calculated results indicate that all LMXBs with a low‐mass donor star of 1.0–2.0 M⊙ and a short orbital period (≲ 3–4 d) can form millisecond pulsars with a spin period less than 10 ms. However, it is difficult to produce submillisecond pulsars by this evolutionary channel. In addition, our evolutionary scenario cannot account for the existence of BMSPs with a long orbital period (Porb≳ 70–80 d).

Formation of Millisecond Pulsars From Intermediate- And Low-Mass X-Ray Binaries

“…The main reason is that we have taken into account the effect of disk instability. The ΔM 1 distribution is roughly in line with Liu & Chen (2011), who found that ΔM 1 is generally less than 0.6 M in their calculations for systems with a 1.4 M NS and a 1.0-2.0 M donor star. Moreover, we find that systems with initially massive NSs (1.8 M ) may accrete enough mass to evolve into BMSPs with 60 days P orb 200 days, while light NSs in wide binaries are more likely to be partially recycled.…”

“…It is expected that the NS has to accrete mass of at least a few ∼0.01 M to reach a millisecond period, but this is difficult to achieve for NSs in wide binaries (see also Liu & Chen 2011) because the mass transfer rate (which increases with increasing orbital period) is likely to be super-Eddington and the accretion disk is likely to be unstable. In Figure 7, we show the mass transfer rate |Ṁ 2 | and the accreted mass ΔM 1 of the NS as a function of the final orbital period P orb .…”

Investigation of some physical properties of accretion induced collapse in producing millisecond pulsars

“…The NS is subsequently spun-up to a high spin frequency via accretion of mass and angular momentum once the secondary star evolves (For a more detailed review, see i.e. Alpar et al (1982); Bhattacharya and van den Heuvel (1991); Tauris et al (2000); Liu and Chen (2011);Tauris (2011)) In this section we will determine the spin period of MSPs originated from WDs, the process begins with simple Keplerian frequency, the angular velocity of the NS is equal to the Keplerian angular velocity of the magnetosphere, at roughly the Alfvén surface,…”

A comparison of millisecond pulsar populations between globular clusters and the Galactic field

“…Many studies have shown that the final state of a MSP strongly depends on the initial mass of its companion and the orbital separation (e.g. Tauris 2011;Liu & Chen 2011). Furthermore, evolutionary status of the compan-ion at the onset of the Roche lobe overflow (RLO) is suggested to be a key factor in determining the timescale of the mass transfer phase which can directly affect the nature of the MSP (Tauris 2011;Tauris & Savonije 1999).…”