Gamma Columbae gained mass, not lost it, study finds

Gamma Columbae has been reclassified as a mass gainer, overturning previous assumptions that suggested it was an envelope-stripped star. We developed an analytic framework independent of specific evolutionary models to constrain the amount and composition of accreted material from observed surface abundances. This method not only constrains mass transfer but also binary mergers, as demonstrated through its application to SN 1987A, and highlights surface abundance measurements as a powerful tool for understanding massive binary systems evolving toward supernovae and compact object binaries. Approximately 70% of massive stars have a stellar companion close enough that mass exchange becomes inevitable, with mass transfer or eventual merging almost certain. Identifying stars that have undergone these interactions, however, remains a…