086544

Accretion disc winds in X-ray binaries are not spherically symmetric structures comma but their solid angle is difficult to determine because we usually only sample specific lines of sight. We can overcome this problem by studying Hercules X-1 comma a binary with a precessing warped disc. Its disc wind is strongly varying within a precession cycle comma indicating a small wind launching angle and strong vertical stratification. However comma the available data originate from many precession cycles and could be plagued by long-term variability effects. With this proposal comma we aim to finely sample the wind vertical structure within a single precession cycle comma free of any long term deviations comma to understand the wind launching angle comma launching mechanism and to measure accurately the mass outflow rate.