The goal of our workshop is to advance towards a unified view of the physics of the stellar winds in massive X-ray binaries bringing together specialists in winds from massive stars, accretion physics, binary evolution and observers of wind-fed systems. Massive stars are among the most important cosmic engines: they trigger the star formation and, together with low-mass stars, enrich the interstellar medium with the heavy elements but on short time scales, ultimately leading to formation of Earth-like planets and development of life.
Among the bright X-ray sources in the sky a significant number consists of a compact object accreting from the wind of such massive stars. These winds are fast, with typical terminal velocities up to 2500 km/s , dense, with mass-loss rates M >1e-7M⊙/yr , and driven by line scattering of the star’s intense continuum radiation field. Good examples are Cyg X-1/HDE 226868, the first detected stellar-mass black hole, and Vela X-1, one of the most important accreting neutron star binaries. While the basic picture has been established for decades, many details are still debated.
The ISSI teams ”Unified View of Stellar Winds in Massive X-ray Binaries” and "A Comprehensive View of Stellar Winds in Massive X-ray Binaries" brought together experts in the field of massive star winds and accreting high mass X-ray binaries. The main goal was to bridge the gap between these two communities in order to consolidate the understanding of fast outflows from massive stars. Thanks to the opportunity offered by ISSI, a solid framework of observational and theoretical results was compiled and research activities along these lines were boosted, publishing the revision paper "Towards a unified view of inhomogeneous stellar winds in isolated supergiant stars and supergiant high mass X-ray binaries". At the same time, the meetings and discussions unveiled major discrepancies between results obtained in high-mass X-ray binaries and in isolated massive stars, which cannot be explained by differences in spectral types. Thus, important physical parameters controlling the wind structure are still not sufficiently understood. This workshop aims at promoting new collaborations inviting experts in fields that have been found to be missing in the two ISSI teams.
SOC: Enrico Bozzo, Silvia Martínez-Núñez, Lida Oskinova and Joachim Puls.
LOC: María Teresa Ceballos, Felix Fürst, Peter Kretschmar and Silvia Martínez-Núñez.