  We explore the sensitivity of massive stars to neutrino magnetic moments. We
find that the additional cooling due to the neutrino magnetic moments bring
about qualitative changes to the structure and evolution of stars in the mass
window 7 Msun < M < 18 Msun, rather than simply changing the time scales for
the burning. We describe some of the consequences of this modified evolution:
the shifts in the threshold masses for creating core-collapse supernovae and
oxygen-neon-magnesium white dwarfs and the appearance of a new type of
supernova in which a partial carbon-oxygen core explodes within a massive star.
The resulting sensitivity to the magnetic moment is at the level of (2-4) *
10^{-11} \mu_B.
