CAN THE SUBSONIC ACCRETION MODEL EXPLAIN THE SPIN PERIOD DISTRIBUTION OF WIND-FED X-RAY PULSARS?

Journal Article · Mon Jun 20 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/824/2/143· OSTI ID:22666143

Li, Tao; Shao, Yong; Li, Xiang-Dong ^[1]

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1. Department of Astronomy, Nanjing University, Nanjing 210023 (China)

Neutron stars in high-mass X-ray binaries (HMXBs) generally accrete from the wind matter of their massive companion stars. Recently, Shakura et al. suggested a subsonic accretion model for low-luminosity (<4 × 10{sup 36} erg s{sup −1}), wind-fed X-ray pulsars. To test the feasibility of this model, we investigate the spin period distribution of wind-fed X-ray pulsars with a supergiant companion star, using a population synthesis method. We find that the modeled distribution of supergiant HMXBs in the spin period–orbital period diagram is consistent with observations, provided that the winds from the donor stars have relatively low terminal velocities (≲1000 km s{sup −1}). The measured wind velocities in several supergiant HMXBs seem to favor this viewpoint. The predicted number ratio of wind-fed X-ray pulsars with persistent X-ray luminosities that are higher and lower than 4 × 10{sup 36} erg s{sup −1} is about 1:10.

• OSTI ID: 22666143
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 824; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMIC X-RAY BURSTS
DISTRIBUTION
LUMINOSITY
MASS
NEUTRON STARS
PULSARS
SPIN
STAR EVOLUTION
SYNTHESIS
VELOCITY
X RADIATION