Temperature of the SN1987A supernova provides an estimate of the   electron neutrino mass
  Numerous estimates of upper bounds on the (anti)neutrino rest mass have been published based on the SN1987A observations.   Here, we use a nonkinematic (thermal) time extent to provide a rest mass estimate of a few eV (as mc^2 mass), if not zero. In the solution, we find that a typical upper bound formula for the mass implies that this thermal extent was attributable to about 10% of the particle energy measured on Earth. The present approach yields an expected value for the mass, given any theoretical or model dependent estimate of the fraction of the detected neutrino energy attributable to the supernova temperature. 
John Michael Williams