Most of the energy released in the collapse of a massive star to a neutron star (a core collapse supernova) is in the form of neutrinos. If the just-formed neutron star has a mass M = 1.4M⊙ and a radius R = 10 km, estimate the mean nucleon density, in cm−3. Find the mean free path, in cm, of a neutrino inside the neutron star, assuming the density you found and a cross section for scattering of neutrinos on neutrons of σνn = 10−42 cm2

Most of the energy released in the collapse of a massive star to a neutron star (a core collapse supernova) is in the form of neutrinos. If the just-formed neutron star has a mass M = 1.4M⊙ and a radius R = 10 km, estimate the mean nucleon density, in cm−3. Find the mean free path, in cm, of a neutrino inside the neutron star, assuming the density you found and a cross section for scattering of neutrinos on neutrons of σνn = 10−42 cm2