An analysis of V 861 Sco – I. Light-curve synthesis

Photometry of V 861 Sco, a binary at one time suspected of containing a collapsed secondary, is analysed using light-curve synthesis techniques. A consistent solution is obtained under the (justified) assumption that the primary fills its Roche lobe; the secondary is found to be of spectral type ∼ B2 V. The absolute dimensions of the components are derived, and the evolutionary status of the system discussed. Infrared and low-resolution IUE data are considered in the framework of the derived model. The stellar wind mass-loss rate is examined, together with the possibility of an apparent phase dependence of this quantity.