At the beginning of the 80’s, big underground detectors were built to search for proton decay, following the predictions of the grand unified theories. No decay has been observed, but, on the 23th of February 1987, two experiments, Kamiokande in Japan and IMB in USA, detected an unexpected signal. During a few seconds, they received a burst of neutrinos having a mean energy of ~10-20 MeV.
It has been associated to the optical observation of SN1987A, a type-II supernova that exploded in the Large Magellanic Cloud, ~150000 years ago [Wik]. The signal (10 events in Kamiokande [Hir87], 8 in IMB [Bio87] and 5 in Baksan [Ale88]) has been interpreted as antineutrino interactions on protons (inverse beta decay).
This was the proof that supernovae emit a huge quantity of neutrinos which take out 99% of the energy of this cosmic explosion. The models describing the core collapse of a supernova show that approximately 3×1053ergs of gravitational binding energy are released in a burst consisting of ~1058 neutrinos in a time interval of a few seconds.
In 1941, Gamow had already anticipated such event [Gam41]: “at the very high temperatures and densities which must exist in the interior of contracting stars during the later stages of their evolution, one must expect a special type of nuclear processes accompanied by the emission of a large number of neutrinos…”.
Core-collapse models have been developed for supernovas (see for example [Bro88,Bet90,Bur90]) and it has been soon supposed that neutrinos could play an active role in the supernova explosion [Lev74]. 3-dimensional models with neutrino-driven explosions have recently made significant progresses [Jan18].
The SN1987A event was the first direct observation in neutrino astronomy. In 2018, we are still eagerly waiting for a new type-II supernova event !