  We consider right handed neutrino emission from charged and neutral pion
condensate matter likely to be present in the supernova core associated with SN
1987 A. This is used to constrain the strength of right handed interaction and
we get excluded range of values for the right handed $W$ boson and extra
neutral $Z'$ boson masses. For vanishing $W_L-W_R$ mixing we obtain $
(1.3-1.8)\,M_{W_L} \,\approx \leq\,M_{W_R} \, \leq\approx 100\, M_{W_L} \, {\rm
and}\, (1.3-1.8)\,M_{W_L}\, \approx \leq \, M_{N'}\,\leq\approx \,225
\,M_{W_L}$
