High Mass X-ray Binaries are excellent laboratories where current models of stellar winds and accretion physics can be tested. In this talk we will present XMM-Newton and Chandra observations of several HMXBs in order to explore the structure of the stellar wind of their massive star donors and its interplay with the accretion onto the neutron star. In particular we will explore the wind clumps providing some direct measurements of their physical properties and how these compare with the theoretical expectations from state of the art stellar wind models. Finally, we will explore briefly the accretion physics onto the magnetized NS and how it is influenced by the stellar wind structure.

The X-ray Universe 2017, Proceedings of the conference held 6-9 June, 2017 in Rome, Italy. Edited by J.-U. Ness and S. Migliari. Online at https://www.cosmos.esa.int/web/xmm-newton/2017-symposium, p.332.

Project ESP2014-53672-C3-3P