Quark deconfinement as a supernova explosion engine for massive blue supergiant stars

Blue supergiant stars develop into core-collapse supernovae-one of the most energetic outbursts in the Universe-when all nuclear burning fuel is exhausted in the stellar core. Previous attempts have failed to explain observed explosions of such stars, which have a zero-age main-sequence mass of 50 M-circle dot or more. Here, we exploit the largely uncertain state of matter at high density, and connect the modelling of such stellar explosions with a first-order phase transition from nuclear matter to the quark-gluon plasma. The resulting energetic supernova explosions can account for a large variety of light curves, from peculiar type II supernovae to superluminous events. The remnants are neutron stars with a quark matter core, known as hybrid stars, of about 2 M-circle dot at birth. A Galactic event of this kind could be observable owing to the release of a second neutrino burst. Its observation would confirm such a first-order phase transition at densities relevant for astrophysics.