On the possibility of disk-fed formation in supergiant high-mass X-ray binaries

TL;DR

This paper investigates the potential for disk-fed accretion in supergiant high-mass X-ray binaries by analyzing neutron star magnetic fields, wind properties, and accretion scenarios, revealing that most systems can be explained by wind accretion with some exceptions.

Contribution

The study introduces a model linking wind velocity, magnetic fields, and mass-loss rates to explain accretion modes in supergiant X-ray binaries, highlighting conditions for wind-fed and disk-fed accretion.

Findings

Most systems (6 of 9) are consistent with wind-fed accretion.

Correlations between mass-loss rate and wind velocity are identified.

Some systems require alternative accretion scenarios like disk formation.

Abstract

We have considered the existence of neutron star magnetic field given by the cyclotron lines. We collected the data of 9 sources of high-mass X-ray binaries with supergiant companions as a case of testing our model, to demonstrate their distribution and evolution. The wind velocity, spin period and magnetic field strength are studied under different mass loss rate. In our model, correlations between mass-loss rate and wind velocity are found and can be tested in further observations. We examined the parameter space where wind accretion is allowed, avoiding barrier of rotating magnetic fields, with robust data of magnetic field of neutron stars. Our model shows that most of sources (6 of 9 systems) can be fed by the wind with relatively slow velocity, and this result is consistent with previous predictions. In a few sources, our model cannot fit under the standard wind accretion scenario. In these peculiar cases, other scenarios (disk formation, partial Roche lobe overflow) should be considered. This would provide information about the evolutionary tracks of various types of binaries, and thus show a clear dichotomy behavior in wind-fed X-ray binary systems.