  The neutrino burst detected during supernova SN1987A is explained in a
strangeon star model, in which it is proposed that a pulsar-like compact object
is composed of strangeons (strangeon: an abbreviation of "strange nucleon"). A
nascent strangeon star's initial internal energy is calculated, with the
inclusion of pion excitation (energy around 10^53 erg, comparable to the
gravitational binding energy of a collapsed core). A liquid-solid phase
transition at temperature ~ 1-2 MeV may occur only a few ten-seconds after
core-collapse, and the thermal evolution of strangeon star is then modeled. It
is found that the neutrino burst observed from SN 1987A could be re-produced in
such a cooling model.
