Born from binary mergers: Supernova 1987A and R Coronae Borealis stars

This thesis studies the origin of two exotic stellar phenomena from the merger of binary stars: Supernova SN 1987A from the merger of massive stars and a rare class of hydrogen-deficient carbon-rich stars called R Coronae Borealis stars from the merger of white dwarfs. This is the first work that confirms that a binary merger was responsible for SN 1987A, by explaining both, the observations of its peculiar blue supergiant progenitor and also of the explosion itself. This is also the first work that explores R Coronae Borealis stars as being a source of certain presolar graphite grains.