Can Fusion Overcome Gravitational Potential Energy in White Dwarf Explosions?

[leonne]

Homework Statement

The explosive fusion occurs in several steps, but the ultimate result is that carbon
is fused into nickel Assuming that the entire white dwarf
is carbon that fuses to nickel, show that the energy released in the explosion
overcomes the gravitational potential energy, thus blowing apart the star.

Homework Equations

U~-GM²/R

The Attempt at a Solution

Ok so iI found how much energy you get when u fuse carbon to nickel 280Mev. Not sure what to do from here. I found the efficiency to be .0018 and was thinking of using
E(nuclear)=eMc² Would this be the energy released?
Than I just set the energy released = to the grav potential energy right?
Thanks for the help

 

[truth is life]

The problem statement says that the entire white dwarf is carbon fusing to nickel. How much energy would that release, given that each fusion process releases 280 MeV?

(They're clearly just going for a reasonable/approximation approach, so you're overthinking it)

 

[leonne]

lol always get a reply back after the homework is due. Well I figured it out, it was exacly what i said , but in the end just have to show E is greater then U