Population synthesis is used to model the number of neutron stars in globular clusters that are observed as low-mass X-ray
sources and millisecond radio pulsars. The dynamical interactions between binary and single stars in a cluster are assumed
to take place only with a continuously replenished “background” of single stars whose properties keep track of the variations
in parameters of the cluster as a whole and the evolution of single stars. We use the hypothesis that the neutron stars forming
in binary systems from components with initial masses of ∼8–12
M
⊙ during the collapse of degenerate O-Ne-Mg cores through electron captures do not acquire a high space velocity. The remaining
neutron stars (from single stars with masses >8
M
⊙ or from binary components with masses >12
M
⊙) are assumed to be born with high space velocities. According to this hypothesis, a sizeable fraction of the forming neutron
stars remain in globular clusters (about 1000 stars in a cluster with a mass of 5 × 10
5
M
⊙). The number of millisecond radio pulsars forming in such a cluster in the case of accretion-driven spinup in binary systems
is found to be ∼10, in agreement with observations. Our modeling also reproduces the observed shape of the X-ray luminosity
function for accreting neutron stars in binary systems with normal and degenerate components and the distribution of spin
periods for millisecond pulsars.
PACS numbers 98.20.Gm - 97.60.Jd - 97.60.Gb - 97.80.Jp - 98.70.Qy
Key words binary X-ray sources - neutron stars - millisecond pulsars - globular clusters
Original Russian Text © A.G. Kuranov, K.A. Postnov, 2006, published in Pis’ma v Astronomicheskiĭ Zhurnal, 2006, Vol. 32, No.
6, pp. 438–451.