  The relative yields of active and sterile neutrinos in the matter with a high
density and different degree of neutronization are calculated. A significant
increase in the proportion of sterile neutrinos produced in superdense matter
when degree of neutronization approaches the value of two is found. The results
obtained can be used in the calculations of the neutrino fluxes for media with
a high density and different neutronization degrees in astrophysical processes
such as the formation of protoneutron core of a supernova.

High Energy Physics - Phenomenology;Solar and Stellar Astrophysics