Massive Supergiants in Focus: Single, Binary and Stellar Merger Pathways across the Hertzsprung–Russell Diagram

In the era of large-scale surveys, the myriad evolutionary paths that massive stars take as members of binary systems, products of stellar mergers or as single stars toward their demise as supernovae and their resultant remnants, require systematic investigation. Central to this are the massive supergiants, which are the brightest stars in stellar populations that can be observed at large distances, but whose origin, evolutionary status and eventual fates are uncertain.

In this meeting, we will unite theorists and observers to develop a holistic framework linking post main-sequence massive stars to their transient endpoints and cumulatively assess:

• Assess the evolutionary connections between different populations of evolved massive stars (e.g. BSGs, YSGs, RSGs, LBVs, B[e]SGs, hypergiants) using their stellar and binary properties (e.g. mass-loss, multiplicity, rotation rates, mergers, runaways, etc.)
• Assess the missing physics in rapid simulations and detailed modelling that could bias current predictions
• Connect the observed diversity of supernovae to supergiant progenitors
• Explore explodability and compact object formation predictions from supergiant models
• Exploit minority binary channels, including semi-detached binaries, Be stars and high-mass X-ray binaries, as laboratories to study mass transfer and constrain binary evolution