Numerical simulation of accretion in a highly obscured high-mass X-ray binary
This movie shows the density of the stellar wind emitted by a blue supergiant star and accreted by a neutron star in a highly obscured high-mass X-ray binary system. The movie is based on numerical simulations performed with a hydrodynamical code.
The blue supergiant star is shown in the lower part of the frame (in blue) and the density of the stellar wind is indicated in a colour scale, where red indicates highest density. The neutron star, which accretes matter from the stellar wind, is located above the supergiant, where the first kink and eddies arise. Due to its small size with respect to the companion, the neutron star is not visible in this visualisation.
The neutron star's gravity deflects the stellar wind, causing the formation of a high-density stream of gas which is visible in the upper part of the frame. The blue supergiant and the neutron star orbit around a common centre of gravity, but their relative motion is not shown in this visualisation (where comoving coordinates have been used).
The dense tail of material trailing the neutron star absorbs the soft X-rays emitted by the accreted material in the vicinity of the neutron star. This effect can be observed by measuring variations in the absorption of soft X-rays as the two components of the binary system move around one another and regularly eclipse one another along the observer's line of sight.