Abstract

Contributed Talk - Splinter MassiveStars

Thursday, 10 September 2026, 17:35   (MW-1050)

Populations of evolved massive binary stars in the Small Magellanic Cloud

C. Schürmann, X.-T. Xu, N. Langer, D. Lennon, M. U. Kruckow, J. Antoniadis, F. Haberl, A. Herrero, M. Kramer, A. Schootemeijer, T. Shenar, T. M. Tauris, and C. Wang
Universiteit van Amsterdam

Binary star evolution, while important to understand in light of most massive stars harbour a close companion with whom they will eventually interact, is subject to large uncertainties. To constrain the efficiency and the stability of the first mass-transfer phase, we conducted population synthesis experiments of post-interaction binary systems at SMC metallicity. We employed a new merger criterion that adjusts self-consistently to any prescribed mass-transfer efficiency. We find that the observed populations cannot be reproduced with a single mass-transfer efficiency, but only with a mass-dependent one. Using this, we are able to reproduce the observed Be/X-ray binary population of the SMC and predict a significant population of OB-type stars with black-hole companions, which we show to have specific observable properties.