Vela X-1 as a laboratory for accretion in High-Mass X-ray Binaries

TL;DR

Vela X-1 serves as a key observational system for testing and refining models of wind accretion processes in high-mass X-ray binaries, combining detailed observational data with recent theoretical developments.

Contribution

This paper reviews observational properties of Vela X-1 and demonstrates its use as a laboratory for testing recent accretion models in high-mass X-ray binaries.

Findings

Vela X-1's observational data supports recent wind accretion models.

The system helps validate theories of matter flow near neutron stars.

It provides insights into wind acceleration and flow structure in HMXBs.

Abstract

Vela X-1 is an eclipsing high mass X-ray binary (HMXB) consisting of a 283s accreting X-ray pulsar in a close orbit of 8.964 days around the B0.5Ib supergiant HD77581 at a distance of just 2.4 kpc. The system is considered a prototype of wind-accreting HMXB and it has been used as a baseline in different theoretical or modelling studies. We discuss the observational properties of the system and the use of the observational data as laboratory to test recent developments in modelling the accretion process in High-Mass X-ray Binaries (e.g., Sander et al. 2018; El Mellah et al. 2018), which range from detailed descriptions of the wind acceleration to modelling of the structure of the flow of matter close to the neutron star and its variations.