Past Events

Massive stars often reside in binary or higher-order stellar systems, where the presence of a companion can significantly impact their evolution through binary interactions. These interacting binaries serve as essential astrophysical laboratories, offering valuable insights into the study of compact objects. Over the past two decades, binary population synthesis (BPS) studies have been used extensively to interpret observations of compact-object binaries, helping to unravel the complex physical processes that lead to their formation. We present POSYDON, an innovative binary population synthesis code that employs full stellar structure and binary-evolution modeling, incorporating MESA code throughout the entire binary evolution. POSYDON stands out by offering a self-consistent treatment of crucial processes such as mass transfer, stability assessment, angular-momentum transport, and tides. Using POSYDON, we have investigated the formation of merging neutron star-black hole (NSBH) binaries at solar metallicity. Our study explores different formation channels, revealing insights that diverge from earlier studies using rapid binary population synthesis codes. We also explored the enigma of black hole-high mass X-ray binaries (BH-HMXBs), particularly delving into the realm of extreme BH spins by considering hypercritical accretion scenarios. With POSYDON, we have discovered several intriguing features of BH-HMXBs that were not revealed in previous rapid (BPS) studies.