Question

1, when a massive star is at the end of its life the inner corner that is perhaps 2 solar masses shrinks in radius from a radius of around 0.01 solar radii to become a neutron star with a radius of just 15 km.

A. calculate the gravitational potential energy of the core Epotential = -0.6(GM^2/R) before and after the collapse in joules

B. Energy is conserved. Whenever something collapses under gravity the decrease in the potential energy releases other forms of energy. Calculate the amount of energy liberated due to the formation of the neutron star.

C. The liberated energy goes into expanding the outer layers of the store at a very high speed, creating neutrinos and producing light which we see as a supernova. Assume that just 1/1000th (0.1%) of this energy emerges as light over a period of 100 days. Determine the luminosity of the star over this period in Watts

D. convert the luminosity of the supernova into solar luminosities. (for comparison the entire Milky Way galaxy has a luminosity of around 2×10^10 solar luminosities

Answer 1

Numerical data on a supernova