The Colloquium takes place every Wednesday at 11:15 AM - Warsaw Copernicus Astronomical Centre online by means of Zoom platform. The Colloquium is given in English and chaired by dr Stanisław Bajtlik (contact mail seminar@camk.edu.pl). People from outside of the Copernicus Center are very welcome to participate. For technical detailes please contact Dr. Stanislaw Bajtlik (bajtlik@camk.edu.pl).
Alex Gormaz Matamala (Astronomical Institute of the Czech Academy of Sciences)
Mass loss shapes the evolution and final fates of massive stars through their OB, RSG and WR phases. Revised line-driven wind prescriptions predict weaker winds during the OB phases, spanning ~90% of a massive star's lifetime. We present evolutionary models from the Galactic Centre (Z=0.020) to the Small Magellanic Cloud (Z=0.002), exploring changes in HR diagram tracks, surface rotation and chemical enrichment. At high metallicity, weaker winds retain outer layers and slow surface chemical evolution; at low metallicity, they enhance rotational mixing and accelerate surface enrichment. At the Galactic Centre, reduced early mass loss yields less homogeneous Wolf-Rayet (WR) stars and fewer hydrogen-free WN stars, improving agreement with observations. We derive H, He and CNO abundances for Ofpe/WN9, WNL, WN/C and WC subtypes and propose a revised subtype classification for wind-collision bow shocks to inform accretion models for Sgr A*. We also investigate how self-consistent wind hydrodynamic profiles, replacing the beta-law, modify wind configurations, hydrogen columns and accretion rates in high-mass X-ray binaries. Finally, we examine line-driven wind prescriptions near the Eddington limit. We introduce an O-to-WR wind-transition criterion to replace the classical hydrogen mass-fraction threshold and study its impact in the generation of black holes progenitors of gravitational waves.
Journal Club takes place on Mondays at 11:15 AM in the Seminar Room. The presentation is given in English and is chaired by Journal Club Coordinators. Anyone interested in giving a Journal Club talk is encouraged to contact the email: journalclub(@camk.edu.pl).
Abbas Askar (NCAC, Warsaw)
Based on https://arxiv.org/pdf/2610.04005 and https://arxiv.org/abs/2505.22102
