Question: where and when are neutrino stars formed? The sun wouldn't form a neutrino star, but would any stars near us do so?

Emma Dean answered on 15 Mar 2016:

Neutron stars are usually formed after a star supernovas. There are many stars that could become neutron stars. Our sun won’t because it doesn’t have enough mass. Interestingly, it is hard to predict which stars will become neutron stars or black holes after they supernovae. This is because we don’t yet know the conditions required to separate these two events. Any star that weighs over 1.5 times the mass of our sun has the potential to become a neutron star.