An international piece of research, led by the Instituto de Astrofísica de Canarias (IAC) has found clues to the nature of some of the brightest and hottest stars in our Universe, called blue supergiants. Although these stars are commonly observed, their origin has been an old puzzle that has been debated for several decades. By simulating novel stellar models and analysing a large data sample in the Large Magellanic Cloud, IAC researchers have found strong evidence that most blue supergiants may have formed from the merger of two stars bound in a binary system. The study is published in the