Ok phyzguy thank you very much for your answer.
Finally I've considered the mass-radio relationship that I previously mencioned and assumed that mass is constant during process.
The result obtained is in order about ##\sim 10^{53}\ \text{erg}## of energy released in the collapse
But how i can relate Mass to Radio, can i use the relationship ##R\sim M^\dfrac{1-n}{3-n}## and then with that initial radii calculate the difference in potential energy between 2 radius?
And why can we assume that potential energy is the only source of energy?
Thanks for you response
Hello everyone.
I am trying to solve a problem whose statement reads as follows:
Neutron stars have radii of ##\sim 10## km. If we assume that before the collapse the nucleus of the white dwarf precursor has a mass equal to that of Chandrasekhar, estimate the energy generated in the collapse...